Number of 7-almost primes 7ap such that 2^n < 7ap <= 2^(n+1).

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =1a(7) =1a(8) =5a(9) =8a(10) =22a(11) =46a(12) =99a(13) =224a(14) =461a(15) =1013a(16) =2093a(17) =4459a(18) =9388a(19) =19603a(20) =40946a(21) =85087a(22) =177200a(23) =366248a(24) =758686a(25) =1565038a(26) =3226717a(27) =6641105a(28) =13648299a(29) =28018956