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A283485
Numbers k such that k![6]-2 is prime, where k![6] = A085158 (k) = sextuple factorial.
1
4, 5, 7, 11, 13, 23, 25, 31, 33, 37, 59, 63, 91, 157, 265, 267, 327, 539, 555, 621, 715, 921, 979, 1633, 1821, 2259, 2697, 2809, 2863, 2935, 4213, 4351, 5937, 6885, 8743, 10761, 15159, 17685, 52075, 55147, 68677, 99655
OFFSET
1,1
COMMENTS
a(43) > 10^5.
The first 10 primes associated with this sequence: 2, 3, 5, 53, 89, 21503, 43223, 1339973, 7577953, 49579073.
MATHEMATICA
MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
Select[Range[2, 50000], PrimeQ[MultiFactorial[#, 6] - 2] &]
Select[Range[100000], PrimeQ[Times@@Range[#, 1, -6]-2]&] (* Harvey P. Dale, Feb 23 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert Price, Mar 08 2017
EXTENSIONS
a(39)-a(42) from Robert Price, Jul 09 2017
STATUS
approved