a(n) = binomial(n+5,5) + 4*binomial(n+4,5) + 4*binomial(n+3,5) + binomial(n+2,5).

Terms

a(0) =1a(1) =10a(2) =49a(3) =165a(4) =440a(5) =1001a(6) =2030a(7) =3774a(8) =6555a(9) =10780a(10) =16951a(11) =25675a(12) =37674a(13) =53795a(14) =75020a(15) =102476a(16) =137445a(17) =181374a(18) =235885a(19) =302785a(20) =384076a(21) =481965a(22) =598874a(23) =737450a(24) =900575a(25) =1091376a(26) =1313235a(27) =1569799a(28) =1864990a(29) =2203015