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 A292365 #20 Oct 11 2019 16:54:16 %S A292365 120,672,1740,7776,19260,20640,21384,21924,22428,25830,31440,55968, %T A292365 93024,101010,106140,143910,151164,198792,246510,309582,326196,411138, %U A292365 421596,428256,499464,523776,590112,639288,697158,870552,941094,958716,1060956,1068210,1087776,1100640,1105884,1269828 %N A292365 Abundant numbers n such that sigma(sigma(n) - 2*n) = sigma(n). %C A292365 A005820 is a subsequence. %C A292365 101010 is the least squarefree term. For 6 <= k <= 8, the smallest squarefree terms with k prime factors are 101010 = 2*3*5*7*13*37, 35574630 = 2*3*5*7*13*83*157, and 401738610 = 2*3*5*7*13*31*47*101. %H A292365 Amiram Eldar, <a href="/A292365/b292365.txt">Table of n, a(n) for n = 1..1210</a> (terms below 4*10^9) %e A292365 120 is a term because sigma(sigma(120) - 240) = sigma(360 - 240) = sigma(120). %t A292365 Select[Range[1.3*^6], (d = DivisorSigma[1, #]; d > 2 # && DivisorSigma[1, d - 2 #] == d) &] (* _Giovanni Resta_, Sep 18 2017 *) %o A292365 (PARI) s(n) = sigma(n); %o A292365 isok(n) = s(n)>2*n && s(s(n)-2*n)==s(n); %Y A292365 Cf. A000203, A005101, A005820. %K A292365 nonn %O A292365 1,1 %A A292365 _Altug Alkan_, Sep 15 2017