525601

Appears in sequences

• a(n) = sum of absolute values of coefficients of (1+x-x^2)^n.at n=16A084611
• a(n) = Sum_{1 <= x_1, x_2, x_3, x_4 <= n} ( n/gcd(x_1, x_2, x_3, x_4, n) )^2.at n=8A372963