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.

A239869 Numbers k that divide A239868(k).

This page as a plain text file.
%I A239869 #11 Sep 08 2022 08:46:07
%S A239869 1,6,7,9,14,21,37,69,670,3471,3477,5160,9500,15432,67054,302224,
%T A239869 791733,861781,1425779,6242689,71511220,187308565,318733908,336841318,
%U A239869 343858368,499742949,4088136488,4172097579,9981207398
%N A239869 Numbers k that divide A239868(k).
%C A239869 A239868 = partial sums of A054024, where A054024(n) = sigma(n) mod n.
%C A239869 Values of k for which A239868(k) / k is an integer.
%C A239869 a(30) > 3*10^11. - _Giovanni Resta_, Mar 29 2014
%e A239869 a(4) = 9 is in the sequence because A239868(9) / 9 = 18 / 9 = 2 is an integer.
%o A239869 (Magma) [n: n in [1..10000] | u eq 0 where u is ((&+[SumOfDivisors (k) mod k: k in [1..n]]) mod n)]
%Y A239869 Cf. A000203, A054024, A239868.
%K A239869 nonn
%O A239869 1,2
%A A239869 _Jaroslav Krizek_, Mar 28 2014
%E A239869 a(16)-a(29) from _Giovanni Resta_, Mar 29 2014