Expansion of (1 + x) * Product_{k>=1} (1 + x^k)/(1 - x^k).

Terms

a(0) =1a(1) =3a(2) =6a(3) =12a(4) =22a(5) =38a(6) =64a(7) =104a(8) =164a(9) =254a(10) =386a(11) =576a(12) =848a(13) =1232a(14) =1768a(15) =2512a(16) =3534a(17) =4926a(18) =6812a(19) =9348a(20) =12736a(21) =17240a(22) =23192a(23) =31016a(24) =41256a(25) =54594a(26) =71890a(27) =94232a(28) =122976a(29) =159816