T(n,4) diagonal of triangle in A095693.

Terms

a(0) =6a(1) =130a(2) =1005a(3) =4830a(4) =17465a(5) =52101a(6) =135135a(7) =314985a(8) =674685a(9) =1349205a(10) =2548546a(11) =4587765a(12) =7925190a(13) =13210190a(14) =21341970a(15) =33540966a(16) =51434520a(17) =77158620a(18) =113477595a(19) =163923760a(20) =232959111a(21) =326161275a(22) =450436025