a(n) = 840*(2*n)!/((n + 4)!*n!).

Terms

a(0) =35a(1) =14a(2) =14a(3) =20a(4) =35a(5) =70a(6) =154a(7) =364a(8) =910a(9) =2380a(10) =6460a(11) =18088a(12) =52003a(13) =152950a(14) =458850a(15) =1400700a(16) =4342170a(17) =13646820a(18) =43421700a(19) =139704600a(20) =454039950a(21) =1489251036a(22) =4925984196a(23) =16419947320a(24) =55124108860a(25) =186281471320a(26) =633357002488