-2661domain: ZAppears in sequencesTriangle, read by rows, where T(0,0) = 1, T(n,k) = (-1)^n*(2n+1)*T(n-1,k) - T(n-1,k-1).at n=16A108083Dirichlet g.f.: zeta(s-3)^2 * (1 - 2^(4-s)) / zeta(s).at n=21A369101Partial alternating sums of the sigma_2 function: a(n) = Sum_{k=1..n} (-1)^(k+1) * sigma_2(k).at n=33A379921