a(n) = 7*(n+1)*binomial(n+2,14).

Terms

a(0) =91a(1) =1470a(2) =12600a(3) =76160a(4) =364140a(5) =1465128a(6) =5155080a(7) =16279200a(8) =47006190a(9) =125847260a(10) =315762216a(11) =748843200a(12) =1690097500a(13) =3650610600a(14) =7582037400a(15) =15201516960a(16) =29520803025a(17) =55688330250a(18) =102301525200a(19) =183413260800a(20) =321546372840a(21) =552150337200a(22) =930092814000