Number of Ulam numbers u (A002858) between powers of 2, 2^n < u <= 2^(n+1).

Terms

a(0) =1a(1) =2a(2) =2a(3) =3a(4) =3a(5) =7a(6) =11a(7) =20a(8) =31a(9) =47a(10) =92a(11) =162a(12) =312a(13) =632a(14) =1235a(15) =2460a(16) =4844a(17) =9665a(18) =19335a(19) =38727a(20) =77569a(21) =155729a(22) =310405a(23) =620596a(24) =1240580a(25) =2481645a(26) =4966229a(27) =9926596a(28) =19855760a(29) =39717367