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A328860
Numbers that are 4-imperfect.
1
993803899780063855042560, 2028353759451110328141864960, 6476620014866676143312363520
OFFSET
1,1
LINKS
Douglas E. Iannucci, On a variation of perfect numbers, INTEGERS: Electronic Journal of Combinatorial Number Theory, 6 (2006), #A41.
Andrew Lelechenko, 4-imperfect numbers, Apr 19 2014.
Michel Marcus, More 4-imperfect numbers, Nov 07 2017.
Michel Marcus, solveIMP PARI script
Michel Marcus, List of 4-imperfect numbers (including the 2 files above), last edit Jun 2019.
Weiyi Zhou and Long Zhu, On k-imperfect numbers, INTEGERS: Electronic Journal of Combinatorial Number Theory, 9 (2009), #A01.
PROG
(PARI) solveIMP(1, 4, 10^24)
CROSSREFS
Cf. A127724 (k-imperfect), A127725 (2-imperfect), A127726 (3-imperfect).
Cf. A309806 (the k values).
Cf. A206369 (the rho function).
Sequence in context: A003806 A257374 A217422 * A377422 A095442 A332605
KEYWORD
nonn,more,bref
AUTHOR
Michel Marcus, Feb 16 2020
STATUS
approved