a(n) = 28*(n+1)*binomial(n+6,8)/3.

Terms

a(0) =28a(1) =336a(2) =2100a(3) =9240a(4) =32340a(5) =96096a(6) =252252a(7) =600600a(8) =1321320a(9) =2722720a(10) =5309304a(11) =9876048a(12) =17635800a(13) =30387840a(14) =50736840a(15) =82372752a(16) =130423524a(17) =201894000a(18) =306205900a(19) =455855400a(20) =667206540a(21) =961440480a(22) =1365682500a(23) =1914330600a(24) =2650611600a(25) =3628392768a(26) =4914279216a(27) =6590029600