A249183 seen as binary numbers.

Terms

a(0) =1a(1) =7a(2) =27a(3) =119a(4) =427a(5) =1799a(6) =6939a(7) =30583a(8) =109227a(9) =458759a(10) =1769499a(11) =7798903a(12) =27984299a(13) =117901063a(14) =454761243a(15) =2004318071a(16) =7158278827a(17) =30064771079a(18) =115964117019a(19) =511101108343