a(n) = A254118(2^n).

Terms

a(0) =1a(1) =2a(2) =6a(3) =20a(4) =13a(5) =179a(6) =546a(7) =762a(8) =1816a(9) =14750a(10) =41855a(11) =130334a(12) =184744a(13) =854072a(14) =3087888a(15) =10703601a(16) =15578299a(17) =96694224a(18) =108119693a(19) =514354272a(20) =1569052954a(21) =7807991046a(22) =23534408763a(23) =39516990609a(24) =76222439041a(25) =402903897267