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 A262619 #22 Dec 17 2017 03:08:33 %S A262619 1,1,1,1,1,1,1,1,3,1,1,1,1,1,3,1,1,1,1,1,3,1,1,1,3,1,3,1,1,1,1,1,3,1, %T A262619 3,1,1,1,3,1,1,1,1,1,3,1,1,1,3,3,3,1,1,1,3,1,3,1,1,1,1,1,5,1,3,1,1,1, %U A262619 3,3,1,1,1,1,3,1,3,1,1,1,5,1,1,1,3,1,3,1,1,1,3,1,3,1,3,1,1,3,5,1,1,1,1,1,3,1 %N A262619 Number of parts in the symmetric representation of sigma(n) in two successive octants of two quadrants. %C A262619 In the diagram of the top view of the pyramid described in A244050 consider a 90-degree sector on two successive octants of two quadrants. The area of the top triangle is equal to 1 and the sum of the areas of all parts (or regions) added at n-th stage equals sigma(n), the sum of the divisors of n. %C A262619 a(n) is also the number of terraces at n-th level (starting from the top) in the mentioned sector of the pyramid. %C A262619 For more information see A237593 and A237270. %H A262619 Antti Karttunen, <a href="/A262619/b262619.txt">Table of n, a(n) for n = 1..5000</a> (computed from the b-file of A237271 provided by Michel Marcus) %F A262619 a(n) = A237271(n), if A237271(n) is odd. %F A262619 a(n) = A237271(n) - 1, if A237271(n) is even. %Y A262619 Cf. A000203, A196020, A235791, A236104, A237270, A237271, A237591, A237593, A244050, A244971, A245092, A262618. %K A262619 nonn %O A262619 1,9 %A A262619 _Omar E. Pol_, Nov 06 2015