Numbers arising from certain regular binary expansions.

Terms

a(0) =0a(1) =1a(2) =2a(3) =7a(4) =12a(5) =29a(6) =58a(7) =123a(8) =240a(9) =501a(10) =998a(11) =2023a(12) =4040a(13) =8137a(14) =16266a(15) =32671a(16) =65300a(17) =130837a(18) =261682a(19) =523827a(20) =1047592a(21) =2096237a(22) =4192366a(23) =8386671a(24) =16773312a(25) =33550545a(26) =67100882a(27) =134210007a(28) =268419484a(29) =536854941