A019423 Numbers whose sum of divisors is a fifth power.

1, 21, 31, 651, 889, 3210, 3498, 3710, 3882, 3910, 4310, 4922, 4982, 5182, 5457, 5885, 6035, 6095, 6307, 6797, 7117, 7327, 7597, 24573, 27559, 71193, 82110, 90510, 94981, 97410, 98671, 99301, 99510, 100110, 103362, 104622, 107778, 108438, 108822

Offset

1,2

Links

Marius A. Burtea, Table of n, a(n) for n = 1..3648 (terms 1..1000 from Donovan Johnson; a(1211) re-indexed and duplicate a(2311) removed by Georg Fischer, Mar 21 2022).

Frits Beukers, Florian Luca and Frans Oort, Power Values of Divisor Sums, The American Mathematical Monthly, Vol. 119, No. 5 (May 2012), pp. 373-380.

Prog

(PARI) lista(nn) = {for (i=1, nn, s = sigma(i); if (s == 1 || ispower(s, 5), print1(i, ", ")); ); } \\ Michel Marcus, Jun 12 2013
(Magma) [n:n in [1..10000]| IsPower(SumOfDivisors(n), 5)]; // Marius A. Burtea, Apr 17 2019

Crossrefs

Cf. A000203, A006532, A019422, A019424, A020477, A048257, A048258.

Sequence in context: A068657 A068671 A166668 * A002639 A054282 A095994

Adjacent sequences: A019420 A019421 A019422 * A019424 A019425 A019426

Keyword

nonn

Author

David W. Wilson

Status

approved