G.f.: Sum_{k>=0} x^(k*(k+1)) / Product_{j=1..k} (1 - x^(2*j-1))^2.

Terms

a(0) =1a(1) =0a(2) =1a(3) =2a(4) =3a(5) =4a(6) =6a(7) =8a(8) =10a(9) =14a(10) =18a(11) =22a(12) =30a(13) =38a(14) =46a(15) =60a(16) =74a(17) =90a(18) =114a(19) =138a(20) =167a(21) =206a(22) =248a(23) =298a(24) =360a(25) =430a(26) =511a(27) =612a(28) =726a(29) =854