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 A335255 #8 May 30 2020 04:08:18 %S A335255 5829840,3414097920,39339578248 %N A335255 Numbers k such that ab(k) + ab(k+1) + ab(k+2) = 0, where ab(k) is the abundance of k (A033880). %C A335255 Equivalently, s(k) + s(k+1) + s(k+2) = k + (k+1) + (k+2), where s(k) is the sum of proper divisors of k (A001065). %C A335255 a(4) > 10^11, if it exists. %C A335255 a(4) > 10^13, if it exists. - _Giovanni Resta_, May 30 2020 %e A335255 5829840 is a term since ab(5829840) + ab(5829841) + ab(5829842) = 8428320 - 5513402 - 2914918 = 0. %t A335255 s[n_] := DivisorSigma[1, n] - n; Select[Range[6 * 10^6], s[#] + s[# + 1] + s[# + 2] == 3*# + 3 &] %Y A335255 Cf. A000203, A001065, A033880, A335254. %K A335255 nonn,hard,bref,more %O A335255 1,1 %A A335255 _Amiram Eldar_, May 28 2020