Number of odd entries in A004001 that are <= 2^n.

Terms

a(0) =1a(1) =2a(2) =2a(3) =3a(4) =6a(5) =12a(6) =27a(7) =55a(8) =115a(9) =235a(10) =490a(11) =994a(12) =2008a(13) =4036a(14) =8120a(15) =16280a(16) =32640a(17) =65344a(18) =130879a(19) =261935a(20) =524057a(21) =1048301a(22) =2096855a(23) =4193951a(24) =8388239a(25) =16776799a(26) =33554339a(27) =67109539a(28) =134220995