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 A292949 #10 Aug 27 2022 13:47:20 %S A292949 1,8,15,24,60,168,512,1023,1536,4092,10752,29127,47360,57120,116508, %T A292949 331520,343976,932064,1556480,1980342,3932040,4404480,106151936, %U A292949 238608384,251650560,312792480,5099962368,6604416000,9623577600,13460388480,58350015360,173238912000,355744082763 %N A292949 Subsequence of terms of A019278 whose sum of divisors is also a term of A019278. %C A292949 A019278 is the sequence of integers x such that sigma(sigma(x))/x is an integer. %H A292949 Giovanni Resta, <a href="/A292949/b292949.txt">Table of n, a(n) for n = 1..38</a> %e A292949 8 is a term since both 8 and 15=sigma(8) are terms of A019278. %o A292949 (PARI) isok(n) = my(sn=sigma(n), ssn=sigma(sn)); (denominator(ssn/n)==1) && (denominator(sigma(ssn)/sn) == 1); %Y A292949 Subsequence of A019278. %K A292949 nonn %O A292949 1,2 %A A292949 _Michel Marcus_, Sep 27 2017