cp's OEIS Frontend

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.

A246855 Numbers k such that sigma(k+5) - sigma(k) = k + 5.

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%I A246855 #32 Aug 12 2025 12:45:06
%S A246855 3577,14773,2843579
%N A246855 Numbers k such that sigma(k+5) - sigma(k) = k + 5.
%C A246855 Also numbers k such that A001065(k+5) = A000203(k). - _Michel Marcus_, Sep 06 2014
%C A246855 a(4) (if it exists) > 10^11. - _Hiroaki Yamanouchi_, Sep 10 2014
%C A246855 a(4) (if it exists) > 10^13. - _Giovanni Resta_, Jul 13 2015
%C A246855 No other terms < 2.7*10^15. - _Jud McCranie_, Jul 27 2025
%e A246855 Number 3577 is in sequence because sigma(3577+5) - sigma(3577) = 7800 - 4218 = 3582 = 3577 + 5.
%t A246855 Select[Range[285*10^4],DivisorSigma[1,#+5]-DivisorSigma[1,#]==#+5&] (* _Harvey P. Dale_, Jun 21 2024 *)
%o A246855 (Magma) [n:n in[1..10^7] | SumOfDivisors(n+5)-SumOfDivisors(n) eq n+5];
%o A246855 (PARI)
%o A246855 for(n=1,10^7,if(sigma(n+5)-sigma(n)==n+5,print1(n,", "))) \\ _Derek Orr_, Sep 05 2014
%Y A246855 Cf. A000203, A067816, A246851, A246852, A246853, A246854.
%K A246855 nonn,bref,more
%O A246855 1,1
%A A246855 _Jaroslav Krizek_, Sep 05 2014