Triangle T(n,k) = binomial(5*n - 4*k, 4*n - 3*k), 0 <= k <= n.

Terms

a(0) =1a(1) =5a(2) =1a(3) =45a(4) =6a(5) =1a(6) =455a(7) =55a(8) =7a(9) =1a(10) =4845a(11) =560a(12) =66a(13) =8a(14) =1a(15) =53130a(16) =5985a(17) =680a(18) =78a(19) =9a(20) =1a(21) =593775a(22) =65780a(23) =7315a(24) =816a(25) =91a(26) =10a(27) =1a(28) =6724520a(29) =736281