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A289698 Numbers k such that k!6 - 27 is prime, where k!6 is the sextuple factorial number (A085158). 1
10, 14, 16, 34, 46, 86, 116, 130, 344, 410, 446, 746, 824, 1580, 1682, 1918, 2684, 2710, 4172, 4754, 6976, 7418, 8788, 11756, 13546, 16048, 17192, 19624, 24026, 28510, 32758, 41780, 42740, 45856, 51050 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Corresponding primes are: 13, 197, 613, 13404133, 24663654373, 37455569511954513919973, ...
a(36) > 10^5.
Terms > 46 correspond to probable primes.
LINKS
Henri & Renaud Lifchitz, PRP Records. Search for n!6-27.
OpenPFGW Project, Primality Tester
EXAMPLE
14!6 - 27 = 14*8*2 - 27 = 197 is prime, so 14 is in the sequence.
MATHEMATICA
MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]];
Select[Range[10, 50000], PrimeQ[MultiFactorial[#, 6] - 27] &]
CROSSREFS
Sequence in context: A213310 A055197 A116610 * A153041 A256471 A250403
KEYWORD
nonn,more
AUTHOR
Robert Price, Jul 09 2017
EXTENSIONS
a(35) from Robert Price, Aug 04 2018
STATUS
approved

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Last modified March 29 07:27 EDT 2024. Contains 371265 sequences. (Running on oeis4.)