Sub-triangle of A060187: even-indexed entries of even-indexed rows.

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =230a(5) =1a(6) =1a(7) =10543a(8) =10543a(9) =1a(10) =1a(11) =331612a(12) =4675014a(13) =331612a(14) =1a(15) =1a(16) =9116141a(17) =906923282a(18) =906923282a(19) =9116141a(20) =1a(21) =1a(22) =237231970a(23) =121383780207a(24) =743288515164a(25) =121383780207a(26) =237231970a(27) =1a(28) =1a(29) =6031771195