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A127726 Numbers n that are 3-imperfect. +0
3
6, 120, 126, 2520, 2640, 30240, 32640, 37800, 37926, 55440, 685440, 758520, 831600, 2600640, 5533920, 6917400, 9102240, 10281600, 11377800, 16687440, 152182800, 206317440, 250311600, 475917120, 866829600, 1665709920, 1881532800 (list; graph; listen)
OFFSET

1,1

COMMENT

The new terms come from the paper by Zhou and Zhu. This sequence also contains n = 9223372034707292160 = 2^31*3*5*17*257*65537, which has the product of five Fermat primes (A019434). For this n, n/3 is a 2-imperfect number (A127725). [From T. D. Noe (noe(AT)sspectra.com), Apr 03 2009]

LINKS

Weiyi Zhou and Long Zhu, On k-imperfect numbers, INTEGERS: Electronic Journal of Combinatorial Number Theory, 9 (2009), #A01. [From T. D. Noe (noe(AT)sspectra.com), Apr 03 2009]

CROSSREFS

Cf. A127724 (k-imperfect numbers).

Sequence in context: A135869 A054957 A081537 this_sequence A117063 A001219 A076233

Adjacent sequences: A127723 A127724 A127725 this_sequence A127727 A127728 A127729

KEYWORD

nonn

AUTHOR

T. D. Noe (noe(AT)sspectra.com), Jan 25 2007

EXTENSIONS

Extended by T. D. Noe (noe(AT)sspectra.com), Apr 03 2009

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Last modified December 20 16:54 EST 2009. Contains 171081 sequences.


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