A336554 Odd numbers k such that rad(k) divides sigma(k).

1, 135, 891, 1521, 3375, 5733, 10935, 11907, 41067, 43875, 84375, 89667, 92781, 98865, 107811, 108927, 154791, 185625, 200655, 216513, 226233, 273375, 274625, 287469, 307125, 336141, 416745, 448335, 480249, 544635, 557375, 570375, 590625, 627669, 628849, 648675, 692055, 823875, 885735, 931095, 968877, 1071875, 1108809, 1131165

Offset: 1

Author

Antti Karttunen, Jul 28 2020

Keywords

• nonn

Comments

Only a minority of terms seem to be also in A228058: 5733, 92781, 2069613, 3341637, 4179357, 5929605, 60998353, 67637349, 89162541 among the first 216, the five of them which occur also in A263983.

Question: Is the intersection with A336553 empty?

Links

• Amiram Eldar, Table of n, a(n) for n = 1..1200 (terms 1..216 from Antti Karttunen)
• Index entries for sequences where odd perfect numbers must occur, if they exist at all.

Crossrefs

Odd terms of A175200.

Cf. A000203, A007947, A228058, A263983.

Cf. also A336553.

Programs

PARI

isA336554(n) = if(!(n%2),0,!(sigma(n) % factorback(factorint(n)[, 1])));