Triangle of central factorial numbers 4^k T(2n+1, 2n+1-2k).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =10a(5) =1a(6) =1a(7) =35a(8) =91a(9) =1a(10) =1a(11) =84a(12) =966a(13) =820a(14) =1a(15) =1a(16) =165a(17) =5082a(18) =24970a(19) =7381a(20) =1a(21) =1a(22) =286a(23) =18447a(24) =273988a(25) =631631a(26) =66430a(27) =1a(28) =1a(29) =455