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 A116028 #11 Jul 15 2021 06:39:20
%S A116028 1,2,15,25,119,157,2413,2623,8415,14962,18303,66078,1031747,62826675,
%T A116028 692799137,759500195,1144100379
%N A116028 Numbers k such that k + sigma(k) + sigma(sigma(k)) is a repdigit.
%C A116028 a(18) > 5*10^9. - _Donovan Johnson_, Feb 18 2013
%e A116028 1031747 + sigma(1031747) + sigma(sigma(1031747)) = 5555555.
%t A116028 repQ[n_]:=Module[{ds=DivisorSigma[1,n]},Count[DigitCount[n+ds+ DivisorSigma[ 1,ds]],0] == 9]; Select[Range[66100],repQ] (* The program generates the first 12 terms of the sequence. To generate more, increase the Range constant, but it will take a long time to run. *) (* _Harvey P. Dale_, Oct 08 2020 *)
%Y A116028 Cf. A010785, A116017.
%K A116028 nonn,base
%O A116028 1,2
%A A116028 _Giovanni Resta_, Feb 13 2006
%E A116028 a(14)-a(17) from _Donovan Johnson_, Feb 18 2013