a(n) is the number of numbers between 1 and 2^m with m-n prime factors (counted with multiplicity), for m sufficiently large.

A052130

a(n) is the number of numbers between 1 and 2^m with m-n prime factors (counted with multiplicity), for m sufficiently large.

Terms

    a(0) =1a(1) =2a(2) =7a(3) =15a(4) =37a(5) =84a(6) =187a(7) =421a(8) =914a(9) =2001a(10) =4283a(11) =9184a(12) =19611a(13) =41604a(14) =87993a(15) =185387a(16) =389954a(17) =817053a(18) =1709640a(19) =3567978a(20) =7433670a(21) =15460810a(22) =32103728a(23) =66567488a(24) =137840687a(25) =285076323a(26) =588891185a(27) =1215204568a(28) =2505088087a(29) =5159284087

External references