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.

A336353 Numbers k such that sigma(k) does not have any prime factor larger than the largest prime factor of k.

This page as a plain text file.
%I A336353 #24 Sep 26 2021 18:56:44
%S A336353 1,3,5,6,7,10,11,13,14,15,17,19,21,22,23,26,28,29,30,31,33,34,35,37,
%T A336353 38,39,40,41,42,43,44,46,47,51,52,53,55,56,57,58,59,61,62,65,66,67,68,
%U A336353 69,70,71,73,74,76,77,78,79,82,83,84,85,86,87,88,89,91,92,93,94,95
%N A336353 Numbers k such that sigma(k) does not have any prime factor larger than the largest prime factor of k.
%C A336353 Note that the terms after 1 do not form a subsequence of A102750: the first counterexample is 343 = 7^3. See A336354.
%H A336353 <a href="/index/O#opnseqs">Index entries for sequences where odd perfect numbers must occur, if they exist at all</a>
%o A336353 (PARI) isA336353(n) = !A336352(n);
%Y A336353 Positions of zeros in A336352.
%Y A336353 Cf. A102750, A336317.
%Y A336353 Subsequences: A000396, A001599, A065091, A105402, A333646 (see comment there), A336354.
%K A336353 nonn
%O A336353 1,2
%A A336353 _Antti Karttunen_, Jul 19 2020