Expansion of Product_{k>=1} ((1 + x^k)/(1 - x^k))^(2^(k-1)).

Terms

a(0) =1a(1) =2a(2) =6a(3) =18a(4) =50a(5) =138a(6) =374a(7) =994a(8) =2610a(9) =6778a(10) =17414a(11) =44346a(12) =112034a(13) =280970a(14) =700038a(15) =1733706a(16) =4269970a(17) =10463154a(18) =25518198a(19) =61962458a(20) =149839602a(21) =360958306a(22) =866405702a(23) =2072579058a(24) =4942074082a(25) =11748730482a(26) =27849974598a(27) =65837539522a(28) =155236876018a(29) =365125130490