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 A053620 #14 Mar 04 2023 11:55:56 %S A053620 1,2,2,3,3,3,4,4,4,5,5,5,6,6,6,7,7,7,7,8,8,8,9,9,9,9,10,10,10,10,11, %T A053620 11,11,11,12,12,12,12,13,13,13,13,14,14,14,14,14,15,15,15,15,16,16,16, %U A053620 16,17,17,17,17,17,18,18,18,18,19,19,19,19,19,20,20 %N A053620 Nearest integer to R(n) = the Riemann prime number formula. %C A053620 This is a good approximation to pi(n), the number of prime numbers <= n. %H A053620 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/RiemannPrimeCountingFunction.html">Riemann Prime Counting Function</a>. %Y A053620 Cf. A000720, A047784, A052434. %K A053620 nonn %O A053620 2,2 %A A053620 _Henry Bottomley_, Mar 21 2000