a(n) = (3*n+4)*binomial(n+7, 7)/4.

Terms

a(0) =1a(1) =14a(2) =90a(3) =390a(4) =1320a(5) =3762a(6) =9438a(7) =21450a(8) =45045a(9) =88660a(10) =165308a(11) =294372a(12) =503880a(13) =833340a(14) =1337220a(15) =2089164a(16) =3187041a(17) =4758930a(18) =6970150a(19) =10031450a(20) =14208480a(21) =19832670a(22) =27313650a(23) =37153350a(24) =49961925a(25) =66475656a(26) =87576984a(27) =114316840a(28) =147939440a(29) =189909720