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 A053246 #15 Oct 27 2023 22:00:45
%S A053246 0,0,2,-2,5,-5,6,-3,4,-7,15,-15,9,-1,6,-14,20,-20,21,-11,3,-13,35,-30,
%T A053246 10,-3,15,-27,41,-41,30,-16,5,-7,42,-54,21,-5,33,-49,53,-53,39,-7,-7,
%U A053246 -25,75,-68,35,-22,25,-45,65,-49,47,-41,9,-31,107,-107,33,7,22,-44,59,-77,57,-31
%N A053246 First differences of chowla(n).
%C A053246 Second differences give A053223, for n>1.
%C A053246 If the first term is changed to 1, this is also the first differences of A001065. - _N. J. A. Sloane_, Jan 17 2023
%H A053246 G. C. Greubel, <a href="/A053246/b053246.txt">Table of n, a(n) for n = 1..10000</a>
%F A053246 a(n) = A053222(n) - 1, for n>1
%p A053246 with(numtheory): seq( sigma(i+1) - sigma(i) - 1, i=2..100); # for n>1
%t A053246 Chowlan[n_] := If[n == 1, 0, DivisorSigma[1, n] - n - 1]; Table[Chowlan[n + 1] - Chowlan[n], {n, 1, 100}] (* _G. C. Greubel_, Sep 03 2018 *)
%t A053246 Differences[Join[{0},Table[DivisorSigma[1,n]-n-1,{n,2,100}]]] (* _Harvey P. Dale_, Dec 19 2022 *)
%o A053246 (Magma) [0] cat [DivisorSigma(1,n+1) - DivisorSigma(1,n) - 1: n in [2..100]]; // _G. C. Greubel_, Sep 03 2018
%o A053246 (PARI) concat([0], vector(100, n, n++; sigma(n+1) - sigma(n) -1)) \\ _G. C. Greubel_, Sep 03 2018
%Y A053246 Cf. A048050, A053222, A053223.
%Y A053246 Cf. also A001065.
%K A053246 sign
%O A053246 1,3
%A A053246 _Asher Auel_, Jan 10 2000