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 A169820 #6 Jun 02 2025 02:12:56 %S A169820 1,2,3,1,5,3,8,1,2,5,1,3,1,1,4,1,7,2,1,1,2,1,3,1,4,1,4,1,2,3,1,3,1,2, %T A169820 3,1,7,1,3,2,3,4,3,1,2,10,1,2,1,2,2,3,4,4,2,2,5,3,1,3,9,2,4,1,1,4,7,3, %U A169820 5,2,4,1,2,1,3,7,5,8,1,1,1,2,2,3,1,5,1,3,3,8,9,3,5,3,2,2,18,2,8,4 %N A169820 1 followed by first differences of A169799. %C A169820 Essentially the second differences of A167209. %H A169820 K. S. Brown, <a href="http://www.mathpages.com/home/kmath509/kmath509.htm">Expulsion Sets</a> %Y A169820 Cf. A167209, A169799. %K A169820 nonn %O A169820 1,2 %A A169820 Entry revised by _N. J. A. Sloane_, Sep 03 2014