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 A246910 #21 Sep 08 2022 08:46:09 %S A246910 1,7,26,30,42,54,69,78,84,94,102,103,114,138,140,174,222,258,354,364, %T A246910 474,476,498,520,532,534,582,618,644,650,762,764,812,834,847,894,978, %U A246910 1002,1036,1038,1050,1182,1185,1194,1204,1214,1362,1372,1398,1434,1487 %N A246910 Numbers n such that sigma(n+sigma(n)) = 3*sigma(n). %C A246910 A246914 gives the primes in this sequence. %H A246910 Martin Møller Skarbiniks Pedersen, <a href="/A246910/b246910.txt">Table of n, a(n) for n = 1..1000</a> %e A246910 Number 26 (with sigma(26) = 42) is in sequence because sigma(26+sigma(26)) = sigma(68) = 126 = 3*42. %p A246910 with(numtheory): A246910:=n->`if`(sigma(n+sigma(n)) = 3*sigma(n),n,NULL): seq(A246910(n), n=1..5000); # _Wesley Ivan Hurt_, Sep 07 2014 %o A246910 (Magma) [n:n in[1..10000] | SumOfDivisors(n+SumOfDivisors(n)) eq 3*SumOfDivisors(n)] %o A246910 (PARI) %o A246910 for(n=1,10^4,if(sigma(n+sigma(n))==3*sigma(n),print1(n,", "))) \\ _Derek Orr_, Sep 07 2014 %Y A246910 Cf. A000203, A246456, A246909, A246911, A246912, A246913, A246914, A272027. %K A246910 nonn %O A246910 1,2 %A A246910 _Jaroslav Krizek_, Sep 07 2014