G.f.: 1 + Sum_{n>=1} a(n)*x^n/(1 - x^n) = Product_{n>=1} (1 + n*x^n).

Terms

a(0) =1a(1) =1a(2) =4a(3) =5a(4) =14a(5) =19a(6) =42a(7) =57a(8) =115a(9) =170a(10) =287a(11) =433a(12) =694a(13) =1061a(14) =1709a(15) =2461a(16) =3740a(17) =5635a(18) =8243a(19) =12256a(20) =18255a(21) =26135a(22) =37826a(23) =54209a(24) =78315a(25) =110488a(26) =159418a(27) =224514a(28) =315414a(29) =442790