C(n+7, 7)*(n+4)*(-1)^(n+1)*16.

Terms

a(0) =-64a(1) =640a(2) =-3456a(3) =13440a(4) =-42240a(5) =114048a(6) =-274560a(7) =604032a(8) =-1235520a(9) =2379520a(10) =-4356352a(11) =7637760a(12) =-12899328a(13) =21085440a(14) =-33488640a(15) =51845376a(16) =-78450240a(17) =116290944a(18) =-169206400a(19) =242070400a(20) =-341003520a(21) =473616000a(22) =-649284480a(23) =879465600a(24) =-1178049600