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%I #5 May 11 2022 22:46:26
%S 1,3,1,6,-3,-6,-1,40,3,-50,-1,73,3,-315,1,1953,1,-2117,7,5625,-13,
%T -16116,27,33728,29,-122648,3,351244,-25,-913057,-81,5447169,89,
%U -7596153,637,22521844,-275,-61171056,-263,177290760,-453,-487655426,-583,1523295127,8121,-4093188035
%N Product_{n>=1} (1 + a(n)*x^n) = 1 + Sum_{n>=1} sigma(n)*x^n, where sigma = A000203.
%F Product_{n>=1} (1 + a(n)*x^n) = 1 + Sum_{n>=1} x^n / (1 - x^n)^2.
%t A[m_, n_] := A[m, n] = Which[m == 1, DivisorSigma[1, n], m > n >= 1, 0, True, A[m - 1, n] - A[m - 1, m - 1] A[m, n - m + 1]]; a[n_] := A[n, n]; a /@ Range[1, 46]
%Y Cf. A000203, A320780, A328776, A353923, A353925, A353926.
%K sign
%O 1,2
%A _Ilya Gutkovskiy_, May 11 2022