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 A055732 #27 Oct 09 2020 03:49:10
%S A055732 0,4,15,68,357,1939,11098,65685,397764,2453911,15353323,97163605,
%T A055732 620646217,3995149838,25885182840,168650876819,1104127111380,
%U A055732 7259025764932,47901523494261,317140339436292,2105877503513609,14020561559878216,93570332318306847,625829902867176558,4194084944321575624,28158446635057280702,189368274899202732322
%N A055732 Number of primes <= 7^n.
%H A055732 David Baugh, <a href="/A055732/b055732.txt">Table of n, a(n) for n = 0..30</a> (terms n = 27..30 found using Kim Walisch's primecount program)
%H A055732 <a href="/index/Pri#primepop">Index entries for sequences related to numbers of primes in various ranges</a>
%F A055732 a(n) = A000720(A000420(n)). - _Michel Marcus_, Aug 25 2014
%t A055732 Table[PrimePi[7^n], {n, 0, 16}]
%o A055732 (PARI) a(n) = primepi(7^n); \\ _Michel Marcus_, Aug 25 2014
%Y A055732 Cf. A006880, A007053 and A040014.
%K A055732 nonn
%O A055732 0,2
%A A055732 _Robert G. Wilson v_, Jun 09 2000
%E A055732 a(17)-a(22) from _Henri Lifchitz_, Nov 11 2012
%E A055732 a(23)-a(26) from _Henri Lifchitz_, Aug 25 2014