The OEIS is supported by the many generous donors to the OEIS Foundation.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.
%I #27 Aug 06 2020 22:04:26
%S 1,2,28,56,60,84,160,168,528,12936,32760,102960,1097280,1778400,
%T 11740302,19183500,25241600,235855620,308308000,317167200,424305000,
%U 459818240,704700000,787200000,924924000,1592025435,2701416960,3812244480
%N Numbers k for which A335915(k), A335915(sigma(k)) and A335915(sigma(sigma(k))) obtain the same value.
%C Numbers k for which A335915(k) = A336455(k) = A336456(k).
%C Numbers k such that both k and sigma(k) are in A336461.
%C Note that a(26) = 1592025435 (originally found by _David A. Corneth_) is an odd term > 1, which factorizes as 3^5 * 7^2 * 11^2 * 5 * 13 * 17, and thus is not of the form of A228058.
%C It appears that if we instead list k such that both k and sigma(k) are in A336458, we will not obtain more than these three terms: 1, 2, 84.
%H <a href="/index/O#opnseqs">Index entries for sequences where odd perfect numbers must occur, if they exist at all</a>
%Y Cf. A000203, A000265, A228058, A335915, A336455, A336456, A336458, A336560.
%Y Intersection of any two of these three sequences: A336461, A336462, A336463.
%K nonn,more
%O 1,2
%A _Antti Karttunen_, Jul 22 2020