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A081712 n! - n# + 1 is prime, where n# is the primorial function. 3


%S 4,6,7,8,10,20,21,26,101,119,172,409,621,1043,1204,1283,1673,2003,

%T 4336,5773,12913,13517

%N n! - n# + 1 is prime, where n# is the primorial function.

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

%H Mike Oakes, <a href="http://groups.yahoo.com/group/primenumbers/message/12028">Primo-factorials</a>.

%H Mike Oakes, <a href="/A081710/a081710.txt">Primo-factorials</a>, message 12028 in primenumbers Yahoo group, Apr 3, 2003. [Cached copy]

%H Joe McLean, <a href="http://web.archive.org/web/20091027034731/http://uk.geocities.com/nassarawa%40btinternet.com/probprim2.htm">Interesting Sources of Probable Primes</a>.

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

%Y Cf. A081710, A081711, A081713.

%K nonn,more,hard

%O 0,1

%A _Mike Oakes_, Apr 04 2003

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

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Last modified December 4 02:40 EST 2021. Contains 349469 sequences. (Running on oeis4.)