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 A069896 #16 Aug 28 2019 04:10:29
%S A069896 0,0,2,2,5,5,6,3,1,7,15,15,9,1,2,14,20,20,21,1,1,13,35,5,5,3,3,27,41,
%T A069896 41,30,2,1,1,6,54,21,1,1,49,53,53,39,1,1,25,75,1,7,2,5,45,65,1,1,1,1,
%U A069896 31,107,107,33,1,2,2,1,77,57,1,1,73,122,122,39,3,3,9,1,89,105,3,1,43
%N A069896 GCD of consecutive values of Chowla's function.
%H A069896 Amiram Eldar, <a href="/A069896/b069896.txt">Table of n, a(n) for n = 1..10000</a>
%F A069896 a(n) = gcd(sigma(n+1)-(n+1)-1, sigma(n)-n-1), for n > 1.
%e A069896 Chowla's function values from 92 to 96 are 75,34,49,24,155: successive values are relatively primes.
%t A069896 m = 100; s = Array[If[# == 1, 0, DivisorSigma[1, #] - # - 1] &, {m}]; GCD[s[[1 ;; m - 1]], s[[2 ;; m]]] (* _Amiram Eldar_, Aug 28 2019 *)
%Y A069896 Cf. A048050, A000203, A001650.
%K A069896 easy,nonn
%O A069896 1,3
%A A069896 _Labos Elemer_, Apr 10 2002
%E A069896 a(1) corrected by _Amiram Eldar_, Aug 28 2019