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A329176
Numbers k such that k![4] - 128 is prime, where k![4] = A007662(k) = quadruple factorial.
0
11, 13, 17, 19, 25, 27, 29, 41, 47, 61, 75, 113, 181, 251, 287, 339, 521, 533, 573, 687, 739, 1015, 1243, 1811, 2073, 2851, 2939, 3421, 4055, 4211, 4477, 5219, 6151, 8851, 9251, 14219, 17123, 21703, 24313, 25053, 28811, 33065, 49305, 50775, 52693, 69805, 82077, 87771
OFFSET
1,1
COMMENTS
a(49) > 10^5.
The first 5 primes associated with this sequence are: 103, 457, 9817, 65707, 5220997.
LINKS
MATHEMATICA
MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
Select[Range[1000], (x = MultiFactorial[#, 4] - 128; x > 0 && PrimeQ[x]) &]
Select[Range[10, 90000], PrimeQ[Times@@Range[#, 1, -4]-128]&] (* Harvey P. Dale, May 13 2022 *)
CROSSREFS
Sequence in context: A293662 A244913 A098415 * A067283 A052259 A103900
KEYWORD
nonn
AUTHOR
Robert Price, Nov 07 2019
STATUS
approved