Triangle read by rows: T(n,k) = (4n-4k+1) * T(n-1,k-1) + (4k-3) * T(n-1,k).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =10a(5) =1a(6) =1a(7) =59a(8) =59a(9) =1a(10) =1a(11) =308a(12) =1062a(13) =308a(14) =1a(15) =1a(16) =1557a(17) =13562a(18) =13562a(19) =1557a(20) =1a(21) =1a(22) =7806a(23) =148527a(24) =352612a(25) =148527a(26) =7806a(27) =1a(28) =1a(29) =39055