a(n) = [x^n] (x - 1)^4/((1 - 2*x)*(x^2 - 3*x + 1)).

Terms

a(0) =1a(1) =1a(2) =4a(3) =11a(4) =30a(5) =81a(6) =217a(7) =578a(8) =1533a(9) =4053a(10) =10690a(11) =28145a(12) =74001a(13) =194370a(14) =510133a(15) =1338077a(16) =3508194a(17) =9194697a(18) =24092281a(19) =63114914a(20) =165317997a(21) =432970149a(22) =1133854594a(23) =2969117921a(24) =7774547745a(25) =20356622466a(26) =53299513957a(27) =139550308013a(28) =365368187298a(29) =956587808313