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 A028499 6-hyperperfect numbers: n = 6*(sigma(n) - n - 1) + 1. 7
 301, 16513, 60110701, 1977225901, 2733834545701, 232630479398401 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS a(7) > 10^17. - Max Alekseyev, Nov 25 2019 (7^k-6)*7^(k-1) is a term for all k in A191469. - Max Alekseyev, Nov 17 2019 336823287227717101 = 7^6*1340243*2136143 is also a term. - Giovanni Resta, Nov 18 2019 LINKS Table of n, a(n) for n=1..6. Antal Bege, 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 Cf. A000396, A007593, A028500, A028501, A028502, A034916, A220290. Sequence in context: A300033 A178267 A296961 * A145123 A068258 A075407 Adjacent sequences: A028496 A028497 A028498 * A028500 A028501 A028502 KEYWORD hard,more,nonn AUTHOR Jud McCranie EXTENSIONS a(5) from Donovan Johnson, Nov 20 2012 a(6) from Donovan Johnson confirmed by Max Alekseyev, Nov 17 2019 STATUS approved

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Last modified August 7 01:21 EDT 2024. Contains 375002 sequences. (Running on oeis4.)