OFFSET
1,1
COMMENTS
(7^k-6)*7^(k-1) is a term for all k in A191469. - Max Alekseyev, Nov 17 2019
LINKS
Max A. Alekseyev, Computing bounded solutions to linear Diophantine equations with the sum of divisors, arXiv:2601.17832 [math.NT], 2026. See p. 9, Table 2.
Antal Bege and Kinga Fogarasi, Generalized perfect numbers, Acta Univ. Sapientiae, Math., 1 (2009), 73-82.
Judson S. McCranie, A Study of Hyperperfect Numbers, Journal of Integer Sequences, Vol. 3 (2000), Article 00.1.3.
Eric Weisstein's World of Mathematics, Hyperperfect Number
PROG
(PARI) isok(n) = 6*(sigma(n) - n - 1) + 1 == n; \\ Michel Marcus, Nov 18 2019
CROSSREFS
KEYWORD
hard,more,nonn
AUTHOR
EXTENSIONS
a(5) from Donovan Johnson, Nov 20 2012
a(6) from Donovan Johnson confirmed by Max Alekseyev, Nov 17 2019
a(7) from Giovanni Resta confirmed by Max Alekseyev, May 23 2025
STATUS
approved
