717081

Appears in sequences

• a(n) = (u+1)^n + (-s-1)^n + (t+1)^n + (-1)^n + (-t+1)^n + (s-1)^n + (-u+1)^n where s = sqrt(2), t = sqrt(2-s), u = sqrt(2+s).at n=13A215503
• a(n) = Sum_{1 <= x_1, x_2 <= n} sigma( ( n/gcd(x_1, x_2, n) )^2 ).at n=26A373132