473129domain: NAppears in sequencesE.g.f.: exp(-Sum_{n>=1} sigma_2(n) * x^n).at n=7A294404Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of e.g.f.: exp(-Sum_{j>=1} sigma_k(j) * x^j).at n=52A294951