A246314(2^n-1).

Terms

a(0) =1a(1) =9a(2) =37a(3) =157a(4) =713a(5) =2737a(6) =11421a(7) =44021a(8) =176801a(9) =683369a(10) =2695829a(11) =10433229a(12) =40796217