pub mod io {
    use std::io::{BufRead, ErrorKind};

    pub fn scan<R: BufRead>(r: &mut R) -> Vec<u8> {
        let mut res = Vec::new();
        loop {
            let buf = match r.fill_buf() {
                Ok(buf) => buf,
                Err(e) if e.kind() == ErrorKind::Interrupted => continue,
                Err(e) => panic!("{}", e), 
            };
            let (done, used, buf) = {
                match buf.iter().position(u8::is_ascii_whitespace) {
                    Some(i) => (i > 0 || res.len() > 0, i + 1, &buf[..i]),
                    None => (buf.is_empty(), buf.len(), buf),
                }
            };
            res.extend_from_slice(buf);
            r.consume(used);
            if done { return res; }
        }
    }

    #[macro_export]
    macro_rules! scan {
        ($r:expr, [$t:tt; $n:expr]) => {
            (0..$n).map(|_| scan!($r, $t)).collect::<Vec<_>>()
        };
        ($r:expr, [$t:tt]) => {
            scan!($r, [$t; scan!($r, usize)])
        };
        ($r:expr, ($($t:tt),*)) => {
            ($(scan!($r, $t)),*)
        };
        ($r:expr, Usize1) => {
            scan!($r, usize) - 1
        };
        ($r:expr, Bytes) => {
            io::scan($r)
        };
        ($r:expr, String) => {
            String::from_utf8(scan!($r, Bytes)).unwrap()
        };
        ($r:expr, $t:ty) => {
            scan!($r, String).parse::<$t>().unwrap()
        };
    }

    #[macro_export]
    macro_rules! input {
        ($r:expr, $($($v:ident)* : $t:tt),* $(,)?) => {
            $(let $($v)* = scan!($r, $t);)*
        };
    }
}

pub mod mod_int {
    use std::fmt;
    use std::ops::*;

    #[derive(Clone, Copy, Debug)]
    pub struct ModInt(u64);

    impl ModInt {
        const MOD: u64 = 1_000_000_007;

        pub fn new(mut x: u64) -> Self {
            if x >= Self::MOD {
                x %= Self::MOD;
            }
            Self(x)
        }

        pub fn zero() -> Self {
            Self(0)
        }

        pub fn one() -> Self {
            Self(1)
        }
    }

    impl From<usize> for ModInt {
        fn from(x: usize) -> Self {
            Self::new(x as u64)
        }
    }

    impl From<i64> for ModInt {
        fn from(mut x: i64) -> Self {
            let m = Self::MOD as i64;
            if x.abs() >= m {
                x %= m;
            }
            if x < 0 {
                x += m
            }
            Self::new(x as u64)
        }
    }

    impl Add for ModInt {
        type Output = Self;

        fn add(self, other: Self) -> Self {
            let mut x = self.0 + other.0;
            if x >= Self::MOD {
                x -= Self::MOD;
            }
            Self(x)
        }
    }

    impl AddAssign for ModInt {
        fn add_assign(&mut self, other: Self) {
            *self = *self + other;
        }
    }

    impl Sub for ModInt {
        type Output = Self;

        fn sub(mut self, other: Self) -> Self {
            if self.0 < other.0 {
                self.0 += Self::MOD;
            }
            Self(self.0 - other.0)
        }
    }

    impl SubAssign for ModInt {
        fn sub_assign(&mut self, other: Self) {
            *self = *self - other;
        }
    }

    impl Mul for ModInt {
        type Output = Self;

        fn mul(self, other: Self) -> Self {
            Self::new(self.0 * other.0)
        }
    }

    impl MulAssign for ModInt {
        fn mul_assign(&mut self, other: Self) {
            *self = *self * other;
        }
    }

    impl fmt::Display for ModInt {
        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
            write!(f, "{}", self.0)
        }
    }

    impl ModInt {
        pub fn pow(mut self, mut n: u64) -> Self {
            let mut res = Self::one();
            while n > 0 {
                if n & 1 == 1 {
                    res *= self;
                }
                self *= self;
                n >>= 1;
            }
            res
        }
        
        pub fn inv(self) -> Self {
            self.pow(Self::MOD - 2)
        }
    }
}

use mod_int::ModInt;

fn run<R: std::io::BufRead, W: std::io::Write>(reader: &mut R, writer: &mut W) {
    input! {
        reader,
        n: usize,
        a: [u64; n],
    }

    let mut ans = ModInt::zero();
    let mut prod = ModInt::one();
    for (i, a) in a.into_iter().enumerate() {
        prod = prod * ModInt::new(a);
        if i + 1 < n {
            ans += prod * ModInt::new(2) * ModInt::new(3).pow(n.saturating_sub(i + 2) as u64);
        } else {
            ans += prod;
        }
    }
    writeln!(writer, "{}", ans).ok();
}

fn main() {
    let (stdin, stdout) = (std::io::stdin(), std::io::stdout());
    let ref mut reader = std::io::BufReader::new(stdin.lock());
    let ref mut writer = std::io::BufWriter::new(stdout.lock());
    run(reader, writer);
}