G.f.: Sum_{k>=0} x^(k*(k+1)) * Product_{j=1..k} 1/(1 - x^j)^4.

Terms

a(0) =1a(1) =0a(2) =1a(3) =4a(4) =10a(5) =20a(6) =36a(7) =60a(8) =98a(9) =156a(10) =250a(11) =396a(12) =631a(13) =992a(14) =1555a(15) =2400a(16) =3673a(17) =5536a(18) =8265a(19) =12176a(20) =17781a(21) =25692a(22) =36846a(23) =52404a(24) =74080a(25) =104028a(26) =145344a(27) =201972a(28) =279420a(29) =384764