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A028501 18-hyperperfect numbers: n = 18*(sigma(n)-n-1) + 1. 3
1333, 1909, 2469601, 893748277, 322685352001 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(6) > 4*10^12. 8992165119733, 42052982615431201 and 1978419655654505210563957 are also terms. - Donovan Johnson, Nov 20 2012

LINKS

Table of n, a(n) for n=1..5.

Judson S. McCranie, A Study of Hyperperfect Numbers, Journal of Integer Sequences, Vol. 3 (2000), Article 00.1.3.

CROSSREFS

Cf. A000396, A007593, A220290, A028499, A028500, A028502, A034916.

Sequence in context: A035862 A003907 A043613 * A183646 A250902 A250946

Adjacent sequences:  A028498 A028499 A028500 * A028502 A028503 A028504

KEYWORD

hard,more,nonn

AUTHOR

Jud McCranie

EXTENSIONS

a(5) from Donovan Johnson, Nov 03 2011

STATUS

approved

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Last modified December 7 11:34 EST 2016. Contains 278874 sequences.