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 A111657 #13 Feb 16 2025 08:32:58 %S A111657 4,4,6,6,6,8,8,8,8,8,9,9,9,9,9,9,9,10,10,10,10,10,10,10,10,10,10,10, %T A111657 12,12,12,12,12,12,12,12,12,12,12,12,12,14,14,14,14,14,14,14,14,14,14, %U A111657 14,14,14,14,14,14,14,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15 %N A111657 n-th composite number appears n-th prime times. %D A111657 T. M. Apostol, Introduction to Analytic Number Theory, Springer-Verlag, 1976, page 2. %H A111657 L. Panaitopol, <a href="http://emis.icm.edu.pl/journals/JIPAM/v2n3/027_01.html">Some Properties of the Series of Composed Numbers</a>, J. Inequalities in Pure and Applied Mathematics. 2(2): Article 38, 2000. %H A111657 J. B. Rosser and L. Schoenfeld, <a href="https://doi.org/10.1215/ijm/1255631807">Approximate formulas for some functions of prime numbers</a>, Illinois J. Math. 6: 64-94 (1962). %H A111657 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CompositeNumber.html">Composite Number</a>. %H A111657 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PrimeNumber.html">Prime Number</a>. %F A111657 A002808(n) appears A000040(n) times. %Y A111657 Cf. A000040, A002808, A111653, A111654, A111655, A111656. %K A111657 easy,nonn %O A111657 1,1 %A A111657 _Jonathan Vos Post_, Aug 12 2005