This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A120037 #7 Jul 06 2012 11:50:57
%S A120037 0,0,0,0,0,1,1,5,8,22,44,96,215,439,959,1967,4185,8735,18143,37695,
%T A120037 77939,161479,332008,684502,1404867,2882712,5904454,12078654,24682057,
%U A120037 50375102,102724466,209250102,425921989,866187909,1760280404,3574740094
%N A120037 Number of 6-almost primes 6ap such that 2^n < 6ap <= 2^(n+1).
%C A120037 The partial sum equals the number of Pi_6(2^n).
%e A120037 (2^6, 2^7] there is one semiprime, namely 96. 64 was counted in the previous entry.
%t A120037 AlmostPrimePi[k_Integer, n_] := Module[{a, i}, a[0] = 1; If[k == 1, PrimePi[n], Sum[PrimePi[n/Times @@ Prime[Array[a, k - 1]]] - a[k - 1] + 1, Evaluate[ Sequence @@ Table[{a[i], a[i - 1], PrimePi[(n/Times @@ Prime[Array[a, i - 1]])^(1/(k - i + 1))]}, {i, k - 1}]]]]]; (* _Eric W. Weisstein_, Feb 07 2006 *)
%t A120037 t = Table[AlmostPrimePi[6, 2^n], {n, 0, 30}]; Rest@t - Most@t
%Y A120037 Cf. A046306, A036378, A120033, A120034, A120035, A120036, A120037, A120038, A120039, A120040, A120041, A120042, A120043.
%K A120037 nonn
%O A120037 0,8
%A A120037 _Jonathan Vos Post_ and _Robert G. Wilson v_, Mar 21 2006