G.f.: (1+x^3)^2/((1-x^2)*(1-x^3)*(1-x^4)).

Terms

a(0) =1a(1) =0a(2) =1a(3) =3a(4) =2a(5) =3a(6) =6a(7) =6a(8) =7a(9) =10a(10) =11a(11) =13a(12) =16a(13) =17a(14) =20a(15) =24a(16) =25a(17) =28a(18) =33a(19) =35a(20) =38a(21) =43a(22) =46a(23) =50a(24) =55a(25) =58a(26) =63a(27) =69a(28) =72a(29) =77