1770751domain: NAppears in sequencesa(n) = 5th Euler polynomial evaluated at 2^n and multiplied by 2.at n=4A020525a(n) = Sum_{1 <= x_1, x_2, x_3, x_4 <= n} gcd(x_1, x_2, x_3, x_4, n)^4.at n=25A372931