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 A055731 #24 Oct 09 2020 03:49:03
%S A055731 0,3,11,47,210,985,4821,24427,126726,669432,3588148,19453038,
%T A055731 106460872,587176205,3259873268,18200088376,102107048666,575281018454,
%U A055731 3253321522134,18459252891532,105048100696856,599403542263094,3428437672359713,19652744592040804,112879982373565581,649538196329702877,3743885544339750283,21612949469350359942,124947894360104092955
%N A055731 Number of primes < 6^n.
%H A055731 David Baugh, <a href="/A055731/b055731.txt">Table of n, a(n) for n = 0..33</a> (terms n = 29..33 found using Kim Walisch's primecount program)
%H A055731 <a href="/index/Pri#primepop">Index entries for sequences related to numbers of primes in various ranges</a>
%F A055731 a(n) = A000720(A000400(n)). - _Michel Marcus_, Oct 05 2020
%t A055731 Table[PrimePi[6^n], {n, 0, 17}]
%o A055731 (PARI) a(n) = primepi(6^n); \\ _Michel Marcus_, Oct 05 2020
%Y A055731 Cf. A006880, A007053 and A040014.
%Y A055731 Cf. A000400, A000720.
%K A055731 nonn
%O A055731 0,2
%A A055731 _Robert G. Wilson v_, Jun 09 2000
%E A055731 a(18)-a(24) from _Henri Lifchitz_, Nov 11 2012
%E A055731 a(25)-a(28) from _Henri Lifchitz_, Aug 25 2014