a(n) = 21*(n+1)*binomial(n+4,9).

Terms

a(0) =126a(1) =1470a(2) =9240a(3) =41580a(4) =150150a(5) =462462a(6) =1261260a(7) =3123120a(8) =7147140a(9) =15315300a(10) =31039008a(11) =59961720a(12) =111105540a(13) =198470580a(14) =343219800a(15) =576609264a(16) =943854450a(17) =1509157650a(18) =2362159800a(19) =3626122500a(20) =5468192730a(21) =8112154050a(22) =11854124100a(23) =17081719200a(24) =24297273000