Expansion of Sum_{k>=0} x^k * Product_{j=1..k} (1 + j*x^j).

Terms

a(0) =1a(1) =1a(2) =2a(3) =2a(4) =4a(5) =6a(6) =9a(7) =12a(8) =22a(9) =32a(10) =45a(11) =70a(12) =98a(13) =153a(14) =231a(15) =318a(16) =452a(17) =685a(18) =933a(19) =1387a(20) =1988a(21) =2769a(22) =3850a(23) =5433a(24) =7622a(25) =10530a(26) =14896a(27) =20635a(28) =28123a(29) =38934