#include using namespace std; using ll = long long; using ull = unsigned long long; using i128 = __int128_t; using pii = pair; using pll = pair; template using vec = vector; template using vvec = vector>; #define rep(i, n) for (int i = 0; i < (n); i++) #define rrep(i, n) for (int i = int(n) - 1; i >= 0; i--) #define all(x) (x).begin(), (x).end() constexpr char ln = '\n'; istream& operator>>(istream& is, __int128_t& x) { x = 0; string s; is >> s; int n = int(s.size()), it = 0; if (s[0] == '-') it++; for (; it < n; it++) x = (x * 10 + s[it] - '0'); if (s[0] == '-') x = -x; return is; } ostream& operator<<(ostream& os, __int128_t x) { if (x == 0) return os << 0; if (x < 0) os << '-', x = -x; deque deq; while (x) deq.emplace_front(x % 10), x /= 10; for (int e : deq) os << e; return os; } template ostream& operator<<(ostream& os, const pair& p) { return os << "(" << p.first << ", " << p.second << ")"; } template ostream& operator<<(ostream& os, const vector& v) { os << "{"; for (int i = 0; i < int(v.size()); i++) { if (i) os << ", "; os << v[i]; } return os << "}"; } template inline int SZ(Container& v) { return int(v.size()); } template inline void UNIQUE(vector& v) { v.erase(unique(v.begin(), v.end()), v.end()); } template inline bool chmax(T1& a, T2 b) { if (a < b) {a = b; return true ;} return false ;} template inline bool chmin(T1& a, T2 b) { if (a > b) {a = b; return true ;} return false ;} inline int topbit(ull x) { return x == 0 ? -1 : 63 - __builtin_clzll(x); } inline int botbit(ull x) { return x == 0 ? 64 : __builtin_ctzll(x); } inline int popcount(ull x) { return __builtin_popcountll(x); } inline int kthbit(ull x, int k) { return (x>>k) & 1; } inline constexpr long long TEN(int x) { return x == 0 ? 1 : TEN(x-1) * 10; } inline void print() { cout << "\n"; } template inline void print(const vector& v) { for (int i = 0; i < int(v.size()); i++) { if (i) cout << " "; cout << v[i]; } print(); } template inline void print(const T& x, const Args& ... args) { cout << x << " "; print(args...); } #ifdef MINATO_LOCAL inline void debug_out() { cerr << endl; } template inline void debug_out(const T& x, const Args& ... args) { cerr << " " << x; debug_out(args...); } #define debug(...) cerr << __LINE__ << " : [" << #__VA_ARGS__ << "] =", debug_out(__VA_ARGS__) #define dump(x) cerr << __LINE__ << " : " << #x << " = " << (x) << endl #else #define debug(...) (void(0)) #define dump(x) (void(0)) #endif struct fast_ios { fast_ios() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_; //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// template struct ModInt { public: static constexpr int mod() { return m; } static ModInt raw(int v) { ModInt x; x._v = v; return x; } ModInt() : _v(0) {} ModInt(long long v) { long long x = (long long)(v % (long long)(umod())); if (x < 0) x += umod(); _v = (unsigned int)(x); } unsigned int val() const { return _v; } ModInt& operator++() { _v++; if (_v == umod()) _v = 0; return *this; } ModInt& operator--() { if (_v == 0) _v = umod(); _v--; return *this; } ModInt operator++(int) { ModInt result = *this; ++*this; return result; } ModInt operator--(int) { ModInt result = *this; --*this; return result; } ModInt& operator+=(const ModInt& rhs) { _v += rhs._v; if (_v >= umod()) _v -= umod(); return *this; } ModInt& operator-=(const ModInt& rhs) { _v -= rhs._v; if (_v >= umod()) _v += umod(); return *this; } ModInt& operator*=(const ModInt& rhs) { unsigned long long z = _v; z *= rhs._v; _v = (unsigned int)(z % umod()); return *this; } ModInt& operator^=(long long n) { ModInt x = *this; *this = 1; if (n < 0) x = x.inv(), n = -n; while (n) { if (n & 1) *this *= x; x *= x; n >>= 1; } return *this; } ModInt& operator/=(const ModInt& rhs) { return *this = *this * rhs.inv(); } ModInt operator+() const { return *this; } ModInt operator-() const { return ModInt() - *this; } ModInt pow(long long n) const { ModInt r = *this; r ^= n; return r; } ModInt inv() const { int a = _v, b = umod(), y = 1, z = 0, t; for (; ; ) { t = a / b; a -= t * b; if (a == 0) { assert(b == 1 || b == -1); return ModInt(b * z); } y -= t * z; t = b / a; b -= t * a; if (b == 0) { assert(a == 1 || a == -1); return ModInt(a * y); } z -= t * y; } } friend ModInt operator+(const ModInt& lhs, const ModInt& rhs) { return ModInt(lhs) += rhs; } friend ModInt operator-(const ModInt& lhs, const ModInt& rhs) { return ModInt(lhs) -= rhs; } friend ModInt operator*(const ModInt& lhs, const ModInt& rhs) { return ModInt(lhs) *= rhs; } friend ModInt operator/(const ModInt& lhs, const ModInt& rhs) { return ModInt(lhs) /= rhs; } friend ModInt operator^(const ModInt& lhs, long long rhs) { return ModInt(lhs) ^= rhs; } friend bool operator==(const ModInt& lhs, const ModInt& rhs) { return lhs._v == rhs._v; } friend bool operator!=(const ModInt& lhs, const ModInt& rhs) { return lhs._v != rhs._v; } friend ModInt operator+(long long lhs, const ModInt& rhs) { return (ModInt(lhs) += rhs); } friend ModInt operator-(long long lhs, const ModInt& rhs) { return (ModInt(lhs) -= rhs); } friend ModInt operator*(long long lhs, const ModInt& rhs) { return (ModInt(lhs) *= rhs); } friend ostream& operator<<(ostream& os, const ModInt& M) { return os << M._v; } friend istream& operator>>(istream& is, ModInt& M) { long long x; is >> x; M = ModInt(x); return is; } private: unsigned int _v; static constexpr unsigned int umod() { return m; } }; constexpr int MOD = 1000000007; //constexpr int MOD = 998244353; using mint = ModInt; struct ModCombination { private: int max_n; vector fac_,facinv_; public: ModCombination() {} ModCombination(int n) : max_n(n), fac_(n+1), facinv_(n+1) { assert(1 <= n); fac_[0] = 1; for (int i = 1; i <= n; i++) fac_[i] = fac_[i-1]*i; facinv_[n] = fac_[n].inv(); for (int i = n; i >= 1; i--) facinv_[i-1] = facinv_[i]*i; } mint fac(int k) const { assert(0 <= k and k <= max_n); return fac_[k]; } mint facinv(int k) const { assert(0 <= k and k <= max_n); return facinv_[k]; } mint invs(int k) const { assert(1 <= k and k <= max_n); return facinv_[k]*fac_[k-1]; } mint P(int n, int k) const { if (k < 0 or k > n) return mint(0); assert(n <= max_n); return fac_[n]*facinv_[n-k]; } mint C(int n, int k) const { if (k < 0 or k > n) return mint(0); assert(n <= max_n); return fac_[n]*facinv_[n-k]*facinv_[k]; } mint H(int n, int k) const { if (n == 0 and k == 0) return mint(1); return C(n+k-1,k); } mint catalan(int n) const { if (n == 0) return mint(1); return C(n*2,n) - C(n*2,n-1); } }; constexpr int bound = 320; int main() { int N; cin >> N; vec A(N+1); rep(i,N) cin >> A[i+1]; vvec B(bound); for (int i = 1; i < bound; i++) B[i].assign(i,mint(0)); vec dp(N+1); dp[1] = 1; for (int i = 1; i <= N; i++) { for (int k = 1; k < bound; k++) { dp[i] += B[k][i%k]; } if (i < N) { if (A[i] < bound) { B[A[i]][i%A[i]] += dp[i]; } else { for (int j = i+bound; j <= N; j++) dp[j] += dp[i]; } if (A[i] != 1) dp[i+1] += dp[i]; } } cout << dp[N] << ln; }