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A064186 Numbers n such that n!+1 and n!-1 have the same number of prime divisors (with repetition). 0
3, 5, 8, 9, 10, 13, 17, 20, 22, 24, 26, 34, 39, 53, 59, 61, 63, 69, 70, 76, 80, 87, 97, 99, 103, 124, 130 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

200, 236, 392 and 634 are terms. - Chai Wah Wu, Jan 03 2020

LINKS

Table of n, a(n) for n=1..27.

MATHEMATICA

Select[Range[30], PrimeOmega[#! - 1] == PrimeOmega[#! + 1] &] (* Amiram Eldar, Dec 01 2019 *)

PROG

(PARI) for(n=2, 100, if(bigomega(n!+1)==bigomega(n!-1), print(n)))

CROSSREFS

Cf. A054990, A054991.

Sequence in context: A191931 A325413 A328066 * A271048 A189127 A189288

Adjacent sequences:  A064183 A064184 A064185 * A064187 A064188 A064189

KEYWORD

more,nonn

AUTHOR

Jason Earls, Sep 20 2001

EXTENSIONS

a(15)-a(25) from Donovan Johnson, Mar 09 2008

Offset corrected by Donovan Johnson, Jul 11 2013

a(26)-a(27) from Amiram Eldar, Dec 01 2019

STATUS

approved

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Last modified October 24 10:03 EDT 2021. Contains 348225 sequences. (Running on oeis4.)