a(n) = A014486(A122231(n)).

Terms

a(0) =42a(1) =212a(2) =992a(3) =3876a(4) =15448a(5) =64644a(6) =252056a(7) =989988a(8) =4108676a(9) =16147220a(10) =63393540a(11) =266083460a(12) =1047285272a(13) =4245874244a(14) =16903342544a(15) =67034166420a(16) =274274527940