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 A289697 Numbers k such that k!6 - 24 is prime, where k!6 is the sextuple factorial number (A085158). 1
 9, 11, 13, 17, 23, 25, 29, 31, 37, 43, 53, 65, 71, 77, 79, 115, 119, 151, 173, 559, 793, 1571, 1715, 1807, 1861, 2047, 2215, 3491, 4751, 6631, 9089, 9139, 9253, 25811, 29491, 29495, 54335, 54991, 66535, 72365 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Corresponding primes are: 3, 31, 67, 911, 21481, 43201, 623621, 1339951, ... a(41) > 10^5. Terms > 43 correspond to probable primes. LINKS Table of n, a(n) for n=1..40. Henri & Renaud Lifchitz, PRP Records. Search for n!6-24. Joe McLean, Interesting Sources of Probable Primes OpenPFGW Project, Primality Tester EXAMPLE 13!6 - 4 = 13*7*1 - 24 = 67 is prime, so 13 is in the sequence. MATHEMATICA MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]]; Select[Range[9, 50000], PrimeQ[MultiFactorial[#, 6] - 24] &] Select[Range[8, 5000], PrimeQ[Times@@Range[#, 1, -6]-24]&] (* Harvey P. Dale, Dec 01 2018 *) CROSSREFS Cf. A007661, A037082, A084438, A123910, A242994. Sequence in context: A225557 A120177 A291350 * A104296 A254936 A117675 Adjacent sequences: A289694 A289695 A289696 * A289698 A289699 A289700 KEYWORD nonn,more AUTHOR Robert Price, Jul 09 2017 EXTENSIONS a(37)-a(40) from Robert Price, Aug 03 2018 STATUS approved

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Last modified November 30 12:26 EST 2023. Contains 367461 sequences. (Running on oeis4.)