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Numbers k such that k!!!! + 1 is prime.
11

%I #13 May 31 2024 19:55:42

%S 0,1,2,4,6,18,38,56,94,118,148,286,1358,1480,1514,2680,2846,4078,4288,

%T 5612,5680,6440,6586,14614,30972,31690,54406

%N Numbers k such that k!!!! + 1 is prime.

%C The search for multifactorial primes started by Ray Ballinger is now continued by a team of volunteers on the website of Ken Davis (see link).

%H Ken Davis, <a href="http://mfprimes.free-dc.org">Status of Search for Multifactorial Primes</a>.

%H Ken Davis, <a href="http://mfprimes.free-dc.org/mfdata/f04p.html">Results for n!4+1</a>.

%Y Cf. A007662 (quadruple factorials), A085147.

%K hard,nonn

%O 1,3

%A _Hugo Pfoertner_, Jun 25 2003

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