A064186 - OEIS

A064186

Numbers n such that n!+1 and n!-1 have the same number of prime divisors (with repetition).

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

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OFFSET

1,1

COMMENTS

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

LINKS

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

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