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

Terms

a(0) =1a(1) =1a(2) =3a(3) =4a(4) =7a(5) =10a(6) =17a(7) =23a(8) =36a(9) =49a(10) =71a(11) =96a(12) =136a(13) =180a(14) =248a(15) =326a(16) =437a(17) =569a(18) =752a(19) =967a(20) =1261a(21) =1609a(22) =2069a(23) =2620a(24) =3335a(25) =4189a(26) =5285a(27) =6595a(28) =8249a(29) =10230