Coefficient of x^n in Product_{k>=1} (1 + x^k)^(k*n).

Terms

a(0) =1a(1) =1a(2) =5a(3) =28a(4) =141a(5) =751a(6) =4064a(7) =22198a(8) =122381a(9) =679375a(10) =3792155a(11) =21263331a(12) =119679000a(13) =675763232a(14) =3826165838a(15) =21715370653a(16) =123502583565a(17) =703694143160