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 A246915 #11 Sep 08 2022 08:46:09
%S A246915 4,7,16,50,494,4485,12585,20606,45590,46761,48614,64785,72609,137853,
%T A246915 169898,196934,224186,321986,363037,466545,474573,532441,702374,
%U A246915 811004,910125,982310,1141281,1282436,1288557,1531245,1602801,1635854,1695705,1842405,2246781,2725802,3018277,3343515
%N A246915 Numbers n such that sigma(n + sigma(n)) = sigma((n+1) + sigma(n+1)).
%C A246915 Numbers n such that A246456(n) = A246456(n+1).
%C A246915 Conjecture: sequence of numbers A246456(a(n)): 12, 24, 48, 168, 2160, 17280, 54720, 77280, 221184, 202176, 185328, 249984, 312480, 599040, 725760, 967680, 864864, 1327104, 1489488, 2048256, 1958400, 2439360, 3110400, 3902976, 4852224, 4713984, … is sequence of any multiples of 12.
%e A246915 Number 16 is in sequence because A246456(4) = A246456(5) = 12.
%t A246915 SequencePosition[Table[DivisorSigma[1,n+DivisorSigma[1,n]],{n,3344000}],{x_,x_}][[All,1]] (* The program takes a long time to run. To generate fewer terms but more quickly, reduce the "n" constant. *) (* _Harvey P. Dale_, Mar 07 2022 *)
%o A246915 (Magma) [n:n in[1..1000000] | SumOfDivisors(n+SumOfDivisors(n)) eq SumOfDivisors(n+1+SumOfDivisors(n+1))]
%o A246915 (PARI)
%o A246915 for(n=1,10^7,if(sigma(n+sigma(n))==sigma(n+1+sigma(n+1)),print1(n,", "))) \\ _Derek Orr_, Sep 07 2014
%Y A246915 Cf. A000203, A246456.
%K A246915 nonn
%O A246915 1,1
%A A246915 _Jaroslav Krizek_, Sep 07 2014
%E A246915 More terms from _Derek Orr_, Sep 07 2014