G.f.: (x+4*x^3+x^5)/((1-x)^2*(1-x^2)^2*(1-x^3)).

Terms

a(0) =0a(1) =1a(2) =2a(3) =9a(4) =17a(5) =37a(6) =63a(7) =108a(8) =165a(9) =252a(10) =358a(11) =506a(12) =684a(13) =917a(14) =1192a(15) =1539a(16) =1941a(17) =2433a(18) =2997a(19) =3670a(20) =4433a(21) =5328a(22) =6332a(23) =7492a(24) =8784a(25) =10257a(26) =11886a(27) =13725a(28) =15745a(29) =18005