a(n) = binomial(n+6,6)*(2n+7)/7.

Terms

a(0) =1a(1) =9a(2) =44a(3) =156a(4) =450a(5) =1122a(6) =2508a(7) =5148a(8) =9867a(9) =17875a(10) =30888a(11) =51272a(12) =82212a(13) =127908a(14) =193800a(15) =286824a(16) =415701a(17) =591261a(18) =826804a(19) =1138500a(20) =1545830a(21) =2072070a(22) =2744820a(23) =3596580a(24) =4665375a(25) =5995431a(26) =7637904a(27) =9651664a(28) =12104136a(29) =15072200