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A063788 Numbers n such that sigma(n) = 2n + Omega(n), where Omega(n) is the number of prime divisors of n (with repetition). 0
18, 88, 4030, 5830, 518656, 13174976, 134094848, 2146926592 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(9) <= 2251798907715584. a(10) <= 633825300114085990300727115776. a(11) <= 2596148429267411760623818083663872. [From Donovan Johnson, Dec 19 2008]

a(9) > 10^13. - Giovanni Resta, Jul 13 2015

LINKS

Table of n, a(n) for n=1..8.

PROG

(PARI) for(n=1, 10^8, if(sigma(n)==2*n+bigomega(n), print(n)))

CROSSREFS

Sequence in context: A250101 A141842 A215191 * A066854 A247901 A059138

Adjacent sequences:  A063785 A063786 A063787 * A063789 A063790 A063791

KEYWORD

more,nonn

AUTHOR

Jason Earls, Aug 16 2001

EXTENSIONS

a(7)-a(8) from Donovan Johnson, Dec 19 2008

STATUS

approved

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Last modified March 8 10:56 EST 2021. Contains 341948 sequences. (Running on oeis4.)