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A283553 Numbers k such that k![4] + 2 is prime, where k![4] = A007662(k) = quadruple factorial. 10

%I

%S 0,1,3,5,7,9,11,13,15,19,27,29,31,43,53,75,143,169,185,235,259,363,

%T 365,457,493,573,777,1273,1275,1865,3621,4523,5291,5845,7185,10183,

%U 12845,15057,16281,17945,18771,22479,27235,28089,31557,39163,45709,46329,52211,77779

%N Numbers k such that k![4] + 2 is prime, where k![4] = A007662(k) = quadruple factorial.

%C a(51) > 10^5.

%C The first 10 primes associated with this sequence: 3, 3, 5, 7, 23, 47, 233, 587, 3467, 65837.

%H C. Caldwell and H. Dubner (Eds): <a href="http://primes.utm.edu/lists/top_ten/">The top ten prime numbers: from the unpublished collections of R. Ondrejka</a> (May 2001), Table 21 F, p. 75

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

%t MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];

%t Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 4] + 2] &]

%Y Cf. A076185, A085158, A094144, A204657.

%K nonn

%O 1,3

%A _Robert Price_, Mar 10 2017

%E a(49)-a(50) from _Robert Price_, Aug 12 2017

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Last modified June 20 04:43 EDT 2021. Contains 345157 sequences. (Running on oeis4.)