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

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =10a(5) =18a(6) =35a(7) =62a(8) =110a(9) =197a(10) =339a(11) =573a(12) =975a(13) =1621a(14) =2674a(15) =4385a(16) =7108a(17) =11422a(18) =18277a(19) =28976a(20) =45648a(21) =71531a(22) =111372a(23) =172416a(24) =265695a(25) =407210a(26) =621143a(27) =943392a(28) =1426414a(29) =2147672