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 A038801 #22 Apr 03 2023 10:36:09
%S A038801 4,8,10,12,15,17,19,22,24,25,29,30,31,34,35,37,39,41,42,46,46,47,50,
%T A038801 52,53,55,57,59,61,62,63,66,66,68,70,72,73,75,77,78,80,81,82,85,87,88,
%U A038801 91,92,93,95,97,97,99,99,101,102,104,106,107,109,111,114,114,115,118,120
%N A038801 Number of primes less than 10n.
%C A038801 For almost all n, that is for a set of density 1, a(n) = a(n-1), and in all cases a(n) <= a(n-1) + 4. - _Charles R Greathouse IV_, Aug 27 2014
%H A038801 Robert G. Wilson v, <a href="/A038801/b038801.txt">Table of n, a(n) for n = 1..10000</a>
%H A038801 Andrew R. Booker, <a href="https://t5k.org/nthprime/">The Nth Prime Page</a>
%H A038801 Thomas R. Nicely, <a href="https://faculty.lynchburg.edu/~nicely/index.html">Some Results of Computational Research in Prime Numbers</a> [See local copy in A007053]
%H A038801 Tomás Oliveira e Silva, <a href="http://sweet.ua.pt/tos/primes.html">Tables of values of pi(x) and of pi2(x)</a>
%t A038801 Table[ PrimePi[ n*10 ], {n, 1, 66}] (* _Robert G. Wilson v_ *)
%o A038801 (PARI) a(n)=primepi(10*n) \\ _Charles R Greathouse IV_, Aug 27 2014
%Y A038801 Cf. A028505, A038812, A038813, A038814, A038815, A038816, A038817, A038818, A038819, A038820, A038821, A080122, A080123, A080124, A080125, A080126, A080127, A080128, A080129.
%K A038801 nonn
%O A038801 1,1
%A A038801 _Jeff Burch_
%E A038801 Edited and corrected by _Robert G. Wilson v_, Jan 29 2003