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 A347273 #52 Sep 30 2021 22:51:29 %S A347273 1,3,4,7,6,11,8,15,13,18,12,23,14,24,23,31,18,35,20,39,32,36,24,47,31, %T A347273 42,40,55,30,59,32,63,48,54,45,71,38,60,56,79,42,83,44,84,73,72,48,95, %U A347273 57,93,72,98,54,107,72,111 %N A347273 Number of positive widths in the symmetric representation of sigma(n). %C A347273 a(n) is also the number of columns that contain ON cells in the ziggurat diagram of n. Both diagrams can be unified in a three-dimensional version. %C A347273 a(n) is also the number of nonzero terms in the n-th row of A249351. %C A347273 The number of widths in the symmetric representation of sigma(n) is equal to 2*n - 1 = A005408(n-1). %C A347273 The sum of the positive widths (also the sum of all widths) of the symmetric representation of sigma(n) equals A000203(n). %C A347273 Indices where a(n) = 2*n - 1 give A174973 and also A238443. %C A347273 a(p) = p + 1, if p is prime. %C A347273 a(n) = 2*n - 1, if and only if A237271(n) = 1. %C A347273 a(n) = A000203(n) if n is a member of A174905. %C A347273 For the definition of "width" see A249351. %F A347273 a(n) = A005408(n-1) - A347361(n). %Y A347273 Cf. A000040, A005408, A174905, A174973, A196020, A235791, A236106, A237270, A237271, A237591, A237593, A238443, A249351 (widths), A253258, A347361. %K A347273 nonn,more %O A347273 1,2 %A A347273 _Omar E. Pol_, Aug 29 2021