G.f.: [Sum_{n>=0} x^(n^2) * (1+x+x^2)^n ]^2.

Terms

a(0) =1a(1) =2a(2) =3a(3) =4a(4) =5a(5) =8a(6) =13a(7) =16a(8) =17a(9) =18a(10) =24a(11) =38a(12) =53a(13) =62a(14) =64a(15) =68a(16) =83a(17) =108a(18) =135a(19) =158a(20) =181a(21) =214a(22) =264a(23) =326a(24) =383a(25) =412a(26) =408a(27) =402a(28) =457a(29) =620