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A114888

Multiperfect numbers, sigma(n) = k*n, which are divisible by their sums of prime factors with and without repetition.

1379454720, 14182439040, 680489641226538823680000, 15229814702070563916152832000, 34111227434420791224041472000, 1423615645454579571642097845619575340668304766095889698652160000000

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OFFSET

1,1

COMMENTS

Conjecture: the sequence is finite.

LINKS

Table of n, a(n) for n=1..6.

Achim Flammenkamp, The Multiply Perfect Numbers Page (See here for the latest information about the search)

Eric Weisstein's World of Mathematics, Multiperfect numbers

EXAMPLE

a(1)= 1379454720 = 2^8*3*5*7*19*37*73;

sopfr(1379454720), with repetition = 160 = 2^5*5;

sopfr(1379454720), without repetition = 146 = 2*73.

CROSSREFS

Cf. A091443, A114887.

Sequence in context: A345010 A338516 A091443 * A347114 A376672 A105015

Adjacent sequences: A114885 A114886 A114887 * A114889 A114890 A114891

KEYWORD

fini,nonn

AUTHOR

Sven Simon, Feb 19 2006

STATUS

approved

URL: https://oeis.org/A114888

⇱ A114888 - OEIS