a(n) = 4*(n+1)*binomial(n+2,8).

Terms

a(0) =28a(1) =288a(2) =1620a(3) =6600a(4) =21780a(5) =61776a(6) =156156a(7) =360360a(8) =772200a(9) =1555840a(10) =2975544a(11) =5441904a(12) =9573720a(13) =16279200a(14) =26860680a(15) =43147632a(16) =67663332a(17) =103831200a(18) =156227500a(19) =230887800a(20) =335675340a(21) =480720240a(22) =678939300