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

Terms

a(0) =1a(1) =5a(2) =23a(3) =90a(4) =317a(5) =1036a(6) =3192a(7) =9358a(8) =26336a(9) =71542a(10) =188440a(11) =483007a(12) =1208275a(13) =2956941a(14) =7093531a(15) =16709523a(16) =38706389a(17) =88281394a(18) =198474497a(19) =440263342a(20) =964424210a(21) =2087882510a(22) =4470194335a(23) =9471079495a(24) =19868723042a(25) =41291454537a(26) =85049747913a(27) =173697766646