The first n digits of the juxtaposition of the base-2 numbers converted to decimal.

Terms

a(0) =1a(1) =3a(2) =6a(3) =13a(4) =27a(5) =55a(6) =110a(7) =220a(8) =441a(9) =882a(10) =1765a(11) =3531a(12) =7063a(13) =14126a(14) =28253a(15) =56507a(16) =113015a(17) =226031a(18) =452062a(19) =904124a(20) =1808248a(21) =3616497a(22) =7232994a(23) =14465988a(24) =28931977a(25) =57863955a(26) =115727910a(27) =231455821a(28) =462911642a(29) =925823285