a(n) is the number whose binary representation is A138145(n).

Terms

a(0) =1a(1) =3a(2) =7a(3) =15a(4) =31a(5) =63a(6) =119a(7) =231a(8) =455a(9) =903a(10) =1799a(11) =3591a(12) =7175a(13) =14343a(14) =28679a(15) =57351a(16) =114695a(17) =229383a(18) =458759a(19) =917511a(20) =1835015a(21) =3670023a(22) =7340039a(23) =14680071a(24) =29360135a(25) =58720263a(26) =117440519a(27) =234881031a(28) =469762055a(29) =939524103