a(n) = 91*(n+1)*binomial(n+3,14)/3.

Terms

a(0) =364a(1) =5915a(2) =50960a(3) =309400a(4) =1485120a(5) =5996172a(6) =21162960a(7) =67016040a(8) =193993800a(9) =520550030a(10) =1308811504a(11) =3109779400a(12) =7030805600a(13) =15210877500a(14) =31638625200a(15) =63520624440a(16) =123512325300a(17) =233272227825a(18) =429006396000a(19) =769953584400