Number of bipartite partitions of n white objects and 3 black ones.

Terms

a(0) =3a(1) =7a(2) =16a(3) =31a(4) =57a(5) =97a(6) =162a(7) =257a(8) =401a(9) =608a(10) =907a(11) =1325a(12) =1914a(13) =2719a(14) =3824a(15) =5313a(16) =7316a(17) =9973a(18) =13495a(19) =18105a(20) =24132a(21) =31938a(22) =42021a(23) =54948a(24) =71484a(25) =92492a(26) =119120a(27) =152686a(28) =194887a(29) =247693