Expansion of 1/(1-x)^(1+2*x).

Terms

a(0) =1a(1) =1a(2) =6a(3) =24a(4) =160a(5) =1100a(6) =9168a(7) =84336a(8) =868544a(9) =9806688a(10) =120754080a(11) =1608251040a(12) =23036978688a(13) =353070167424