using System; using System.Linq; using System.Linq.Expressions; using System.Collections.Generic; using Debug = System.Diagnostics.Debug; using StringBuilder = System.Text.StringBuilder; using System.Numerics; using Point = System.Numerics.Complex; using Number = System.Int32; namespace Program { public class Solver { public void Solve() { var n = sc.Integer(); var a = sc.Integer(n); var gcd = MathEx.GCD(a); var L = a.Sum(); var table = new ModTable(L + 1); var div = MathEx.GetDivisors(gcd); div.Sort(); var cnt = new int[div.Count]; for (int i = 0; i < div.Count; i++) { var x = div[i]; for (int v = 2; v * v <= x; v++) { while (x % v == 0) { cnt[i]++; x /= v; } } if (x > 1) cnt[i]++; } var dp = new ModInteger[div.Count]; for (int i = 0; i < div.Count; i++) dp[i].num = -1; Func dfs = null; dfs = (p) => { if (dp[p].num != -1) return dp[p]; ModInteger ret = 0; { ModInteger val = 1L; var len = 0; foreach (var x in a) { val *= table.RepeatedCombination(len + 1, x / div[p]); len += x / div[p]; } ret += val; } for (int i = p + 1; i < div.Count; i++) { if (div[i] % div[p] != 0) continue; ret -= dfs(i); } return dp[p] = ret; }; dfs(0); ModInteger ans = 0; for (int i = 0; i < div.Count; i++) ans += dp[i] * ModInteger.Inverse(L / div[i]); IO.Printer.Out.WriteLine(ans); } public IO.StreamScanner sc = new IO.StreamScanner(Console.OpenStandardInput()); static T[] Enumerate(int n, Func f) { var a = new T[n]; for (int i = 0; i < n; ++i) a[i] = f(i); return a; } static public void Swap(ref T a, ref T b) { var tmp = a; a = b; b = tmp; } } } #region main static class Ex { static public string AsString(this IEnumerable ie) { return new string(System.Linq.Enumerable.ToArray(ie)); } static public string AsJoinedString(this IEnumerable ie, string st = " ") { return string.Join(st, ie); } static public void Main() { var solver = new Program.Solver(); solver.Solve(); Program.IO.Printer.Out.Flush(); } } #endregion #region Ex namespace Program.IO { using System.IO; using System.Text; using System.Globalization; public class Printer : StreamWriter { static Printer() { Out = new Printer(Console.OpenStandardOutput()) { AutoFlush = false }; } public static Printer Out { get; set; } public override IFormatProvider FormatProvider { get { return CultureInfo.InvariantCulture; } } public Printer(System.IO.Stream stream) : base(stream, new UTF8Encoding(false, true)) { } public Printer(System.IO.Stream stream, Encoding encoding) : base(stream, encoding) { } public void Write(string format, T[] source) { base.Write(format, source.OfType().ToArray()); } public void WriteLine(string format, T[] source) { base.WriteLine(format, source.OfType().ToArray()); } } public class StreamScanner { public StreamScanner(Stream stream) { str = stream; } public readonly Stream str; private readonly byte[] buf = new byte[1024]; private int len, ptr; public bool isEof = false; public bool IsEndOfStream { get { return isEof; } } private byte read() { if (isEof) return 0; if (ptr >= len) { ptr = 0; if ((len = str.Read(buf, 0, 1024)) <= 0) { isEof = true; return 0; } } return buf[ptr++]; } public char Char() { byte b = 0; do b = read(); while ((b < 33 || 126 < b) && !isEof); return (char)b; } public string Scan() { var sb = new StringBuilder(); for (var b = Char(); b >= 33 && b <= 126; b = (char)read()) sb.Append(b); return sb.ToString(); } public string ScanLine() { var sb = new StringBuilder(); for (var b = Char(); b != '\n'; b = (char)read()) if (b == 0) break; else if (b != '\r') sb.Append(b); return sb.ToString(); } public long Long() { if (isEof) return long.MinValue; long ret = 0; byte b = 0; var ng = false; do b = read(); while (b != 0 && b != '-' && (b < '0' || '9' < b)); if (b == 0) return long.MinValue; if (b == '-') { ng = true; b = read(); } for (; true; b = read()) { if (b < '0' || '9' < b) return ng ? -ret : ret; else ret = ret * 10 + b - '0'; } } public int Integer() { return (isEof) ? int.MinValue : (int)Long(); } public double Double() { var s = Scan(); return s != "" ? double.Parse(s, CultureInfo.InvariantCulture) : double.NaN; } private T[] enumerate(int n, Func f) { var a = new T[n]; for (int i = 0; i < n; ++i) a[i] = f(); return a; } public char[] Char(int n) { return enumerate(n, Char); } public string[] Scan(int n) { return enumerate(n, Scan); } public double[] Double(int n) { return enumerate(n, Double); } public int[] Integer(int n) { return enumerate(n, Integer); } public long[] Long(int n) { return enumerate(n, Long); } } } #endregion #region ModNumber public partial struct ModInteger { public const long Mod = (long)1e9 + 7; public long num; public ModInteger(long n) : this() { num = n % Mod; if (num < 0) num += Mod; } public override string ToString() { return num.ToString(); } public static ModInteger operator +(ModInteger l, ModInteger r) { var n = l.num + r.num; if (n >= Mod) n -= Mod; return new ModInteger() { num = n }; } public static ModInteger operator -(ModInteger l, ModInteger r) { var n = l.num + Mod - r.num; if (n >= Mod) n -= Mod; return new ModInteger() { num = n }; } public static ModInteger operator *(ModInteger l, ModInteger r) { return new ModInteger(l.num * r.num); } public static ModInteger operator ^(ModInteger l, long r) { return ModInteger.Pow(l, r); } public static implicit operator ModInteger(long n) { return new ModInteger(n); } public static ModInteger Pow(ModInteger v, long k) { ModInteger ret = 1; var n = k; for (; n > 0; n >>= 1, v *= v) { if ((n & 1) == 1) ret = ret * v; } return ret; } } #endregion #region Inverse public partial struct ModInteger { static public ModInteger Inverse(ModInteger v) { long p, q; ExGCD(v.num, Mod, out p, out q); return new ModInteger(p % Mod + Mod); } static public long ExGCD(long a, long b, out long x, out long y) { var u = new long[] { a, 1, 0 }; var v = new long[] { b, 0, 1 }; while (v[0] != 0) { var t = u[0] / v[0]; for (int i = 0; i < 3; i++) { var tmp = u[i] - t * v[i]; u[i] = v[i]; v[i] = tmp; } } x = u[1]; y = u[2]; if (u[0] > 0) return u[0]; for (int i = 0; i < 3; i++) u[i] = -u[i]; return u[0]; } } #endregion #region ModTable public class ModTable { public ModInteger[] perm, inv; public ModTable(int n) { perm = new ModInteger[n + 1]; inv = new ModInteger[n + 1]; perm[0] = 1; for (int i = 1; i <= n; i++) perm[i] = perm[i - 1] * i; inv[n] = ModInteger.Inverse(perm[n]); for (int i = n - 1; i >= 0; i--) inv[i] = inv[i + 1] * (i + 1); inv[0] = inv[1]; } public ModInteger Inverse(int k) { return inv[k]; } public ModInteger Permutation(int n, int k) { if (n < 0 || n >= perm.Length) return 0; if (k < 0 || k >= n) return 0; return perm[n] * inv[n - k]; } public ModInteger Combination(int n, int r) { if (n < 0 || n >= perm.Length || r < 0 || r > n) return 0; return perm[n] * inv[n - r] * inv[r]; } public ModInteger RepeatedCombination(int n, int k) { if (k == 0) return 1; return Combination(n + k - 1, k); } } #endregion #region gcd,lcm static public partial class MathEx { static public Number GCD(Number x, Number y) { byte i = 0; while (x != 0 && y != 0) { if (i == 0) y %= x; else x %= y; i ^= 1; } return x == 0 ? y : x; } static public Number LCM(Number x, Number y) { return (x / GCD(x, y)) * y; } static public Number GCD(params Number[] a) { var gcd = a[0]; foreach (var x in a) gcd = GCD(gcd, x); return gcd; } } #endregion #region Divisors public static partial class MathEx { static public List GetDivisors(Number v) { var ret = new List(); for (Number i = 1; i * i <= v; i++) { if (v % i != 0) continue; ret.Add(i); if (v / i != i) ret.Add(v / i); } ret.Sort(); return ret; } } #endregion