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 A244444 #52 May 23 2025 14:40:47 %S A244444 4,5,506311,4761903,506767303,5517762660583,5554746531623, %T A244444 5555541480743,5458110152757191 %N A244444 Numbers n such that n+sigma(n) is a repunit number. %C A244444 The numbers 47379454926624737751 and 546139199807860751551844463475591 belong to this sequence. - _Giovanni Resta_, Aug 17 2019 %C A244444 Also in the sequence is 38808343270779723425176258917550576371890625326889683884600092615. - _Daniel Suteu_, Aug 23 2019 %e A244444 sigma(4761903)+4761903 = 11111111. %o A244444 (PARI) %o A244444 for(n=1, 10^10, d=digits(sigma(n)+n); if(vecmax(d)==1&&vecmin(d)==1, print1(n, ", "))) \\ _Derek Orr_, Aug 02 2014 %o A244444 (Python) from sympy import divisors %o A244444 [n for n in range(1,10**6) if len(set(str(n+sum(divisors(n))))) == 1 and str(n+sum(divisors(n)))[0] == '1'] # _Chai Wah Wu_, Aug 04 2014 %Y A244444 Subsequence of A116017. %Y A244444 Cf. A309835. %K A244444 nonn,base,more,hard %O A244444 1,1 %A A244444 _Farideh Firoozbakht_, Aug 01 2014 %E A244444 a(5) from _Hiroaki Yamanouchi_, Aug 26 2014 %E A244444 a(6)-a(8) from _Giovanni Resta_, Aug 17 2019 %E A244444 a(9) from _Daniel Suteu_ confirmed by _Max Alekseyev_, May 23 2025