-3126

Appears in sequences

• Sum_{d divides n} (-d)^d.at n=4A076723
• Expansion of 1/(1-2*x+x^2+2*x^3).at n=15A077942
• Dirichlet inverse of A001160, sigma_5.at n=4A178448
• Square array T(n,k), n >= 1, k >= 0, read by antidiagonals downwards, where T(n,k) = Sum_{d|n} mu(d)*mu(n/d)*d^k.at n=49A347227
• a(n) = Sum_{d|n} mu(d)*mu(n/d)*d^n.at n=4A347251