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A283553
Numbers k such that k![4] + 2 is prime, where k![4] = A007662(k) = quadruple factorial.
10
0, 1, 3, 5, 7, 9, 11, 13, 15, 19, 27, 29, 31, 43, 53, 75, 143, 169, 185, 235, 259, 363, 365, 457, 493, 573, 777, 1273, 1275, 1865, 3621, 4523, 5291, 5845, 7185, 10183, 12845, 15057, 16281, 17945, 18771, 22479, 27235, 28089, 31557, 39163, 45709, 46329, 52211, 77779
OFFSET
1,3
COMMENTS
a(51) > 10^5.
The first 10 primes associated with this sequence: 3, 3, 5, 7, 23, 47, 233, 587, 3467, 65837.
MATHEMATICA
MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 4] + 2] &]
Select[Range[0, 78000], PrimeQ[Times@@Range[#, 1, -4]+2]&] (* Harvey P. Dale, Aug 16 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert Price, Mar 10 2017
EXTENSIONS
a(49)-a(50) from Robert Price, Aug 12 2017
STATUS
approved