a(n) = 6*binomial(n+1, 6).

Terms

a(0) =6a(1) =42a(2) =168a(3) =504a(4) =1260a(5) =2772a(6) =5544a(7) =10296a(8) =18018a(9) =30030a(10) =48048a(11) =74256a(12) =111384a(13) =162792a(14) =232560a(15) =325584a(16) =447678a(17) =605682a(18) =807576a(19) =1062600a(20) =1381380a(21) =1776060a(22) =2260440a(23) =2850120a(24) =3562650a(25) =4417686a(26) =5437152a(27) =6645408a(28) =8069424a(29) =9738960