G.f. : 1/(1-2x-23x^2)^(1/2).

Terms

a(0) =1a(1) =1a(2) =13a(3) =37a(4) =289a(5) =1201a(6) =7741a(7) =38053a(8) =227137a(9) =1207009a(10) =6995053a(11) =38591653a(12) =221446369a(13) =1245188881a(14) =7130897437a(15) =40516456357a(16) =232260610177