Duplicate of A076698.

Terms

a(0) =2a(1) =3a(2) =7a(3) =15a(4) =31a(5) =94a(6) =95a(7) =191a(8) =383a(9) =767a(10) =1535a(11) =3071a(12) =6143a(13) =12287a(14) =36862a(15) =36863a(16) =73727