Expansion of Product_{k>=1} 1/(1 - x^k)^(k^2*(k+1)/2).

Terms

a(0) =1a(1) =1a(2) =7a(3) =25a(4) =86a(5) =269a(6) =862a(7) =2606a(8) =7812a(9) =22704a(10) =64989a(11) =182356a(12) =504414a(13) =1373694a(14) =3693367a(15) =9804435a(16) =25733084a(17) =66808578a(18) =171719539a(19) =437183839a(20) =1103143657a(21) =2760037810a(22) =6850400668a(23) =16873338215a(24) =41260373472a(25) =100196920196a(26) =241712863504a(27) =579416535973