A336464 Numbers k for which A335915(k), A335915(sigma(k)) and A335915(sigma(sigma(k))) obtain the same value.

1, 2, 28, 56, 60, 84, 160, 168, 528, 12936, 32760, 102960, 1097280, 1778400, 11740302, 19183500, 25241600, 235855620, 308308000, 317167200, 424305000, 459818240, 704700000, 787200000, 924924000, 1592025435, 2701416960, 3812244480

Offset: 1

Author

Antti Karttunen, Jul 22 2020

Keywords

• nonn
• more

Comments

Numbers k for which A335915(k) = A336455(k) = A336456(k).

Numbers k such that both k and sigma(k) are in A336461.

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.

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.

Links

• Index entries for sequences where odd perfect numbers must occur, if they exist at all

Crossrefs

Cf. A000203, A000265, A228058, A335915, A336455, A336456, A336458, A336560.

Intersection of any two of these three sequences: A336461, A336462, A336463.