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 A055729 #31 Jun 14 2025 13:33:50
%S A055729 0,2,4,9,22,53,129,327,847,2227,5968,16097,43934,120739,334349,931260,
%T A055729 2607165,7332159,20700806,58648288,166677978,475023803,1357200840,
%U A055729 3886548158,11152818693,32064929886,92349038518,266398236486,769616513836,2226457080707,6449247674296,18703411700669,54301968156067,157820174545456
%N A055729 Number of primes <= 3^n.
%H A055729 Robert Price, <a href="/A055729/b055729.txt">Table of n, a(n) for n = 0..51</a> (terms 0..49 from Henri Lifchitz)
%H A055729 <a href="/index/Pri#primepop">Index entries for sequences related to numbers of primes in various ranges</a>
%F A055729 a(n) = A000720(A000244(n)). - _Michel Marcus_, Aug 25 2014
%t A055729 Table[PrimePi[3^n], {n, 0, 29}]
%o A055729 (PARI) a(n) = primepi(3^n); \\ _Michel Marcus_, Aug 25 2014
%Y A055729 Cf. A006880 and A007053.
%K A055729 nonn
%O A055729 0,2
%A A055729 _Robert G. Wilson v_, Jun 09 2000
%E A055729 a(28)-a(40) from _Henri Lifchitz_, Nov 11 2012