a(n) = A169780(2^n).

Terms

a(0) =1a(1) =3a(2) =9a(3) =29a(4) =99a(5) =361a(6) =1373a(7) =5349a(8) =21109a(9) =83859a(10) =334275a(11) =1334769a(12) =5334413a(13) =21328351a(14) =85294869