Number of 5 X n nonconsecutive chess tableaux.

Terms

a(0) =1a(1) =1a(2) =2a(3) =7a(4) =35a(5) =212a(6) =1421a(7) =10128a(8) =75724a(9) =593905a(10) =4927764a(11) =43884083a(12) =426665219a(13) =4591883867a(14) =54943702996a(15) =725753304587