G.f.: (1+14*x+x^2)^3/((1-x))^4.

Terms

a(0) =1a(1) =46a(2) =769a(3) =5632a(4) =18688a(5) =44032a(6) =85760a(7) =147968a(8) =234752a(9) =350208a(10) =498432a(11) =683520a(12) =909568a(13) =1180672a(14) =1500928a(15) =1874432a(16) =2305280a(17) =2797568a(18) =3355392a(19) =3982848a(20) =4684032a(21) =5463040a(22) =6323968a(23) =7270912a(24) =8307968a(25) =9439232a(26) =10668800a(27) =12000768a(28) =13439232a(29) =14988288