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 A213533 #7 Feb 04 2017 01:21:14 %S A213533 0,0,0,0,0,0,3,19,183,1601,14598,130117 %N A213533 Number of k < 10^n such that A047988(k) = 4. %D A213533 Thomas Kantke, Mathematische Unterhaltungen, in: Spektrum der Wissenschaft 4/1993, p. 11-13. %D A213533 Thomas Kantke, Das Spiel Minimum, in: Spektrum der Wissenschaft Spezial Physik - Mathematik - Technik 2/2012, pp. 57-66. %Y A213533 Cf. A047987, A047988, A212524, A213530, A213531, A213532. %K A213533 nonn %O A213533 1,7 %A A213533 _Martin Renner_, Jun 13 2012