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A081712 n! - n# + 1 is prime, where n# is the primorial function. 3
4, 6, 7, 8, 10, 20, 21, 26, 101, 119, 172, 409, 621, 1043, 1204, 1283, 1673, 2003, 4336, 5773, 12913, 13517 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Some of the larger entries may only correspond to probable primes.

LINKS

Table of n, a(n) for n=0..21.

Mike Oakes, Primo-factorials.

Mike Oakes, Primo-factorials, message 12028 in primenumbers Yahoo group, Apr 3, 2003. [Cached copy]

Joe McLean, Interesting Sources of Probable Primes.

EXAMPLE

a(1)=4 because 4!-4#+1=19 is prime

CROSSREFS

Cf. A081710, A081711, A081713.

Sequence in context: A284623 A139490 A030375 * A178663 A084395 A047291

Adjacent sequences:  A081709 A081710 A081711 * A081713 A081714 A081715

KEYWORD

nonn,more,hard

AUTHOR

Mike Oakes, Apr 04 2003

EXTENSIONS

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008

STATUS

approved

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Last modified October 25 11:00 EDT 2021. Contains 348239 sequences. (Running on oeis4.)