A283224 Expansion of exp( Sum_{n>=1} sigma_2(2*n)*x^n/n ) in powers of x.

1, 5, 23, 90, 317, 1036, 3192, 9358, 26336, 71542, 188440, 483007, 1208275, 2956941, 7093531, 16709523, 38706389, 88281394, 198474497, 440263342, 964424210, 2087882510, 4470194335, 9471079495, 19868723042, 41291454537, 85049747913, 173697766646

Offset: 0

Author

Seiichi Manyama, Mar 03 2017

Keywords

• nonn

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. exp( Sum_{n>=1} sigma_k(2*n)*x^n/n ): A182818 (k=1), this sequence (k=2).

Cf. exp( Sum_{n>=1} sigma_2(m*n)*x^n/n ): A000219 (m=1), this sequence (m=2), A283238 (m=3).

Formula

a(n) = (1/n)*Sum_{k=1..n} sigma_2(2*k)*a(n-k). - Seiichi Manyama, Mar 04 2017