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 A291347 Numbers k such that k!4 + 2^6 is prime, where k!4 = k!!!! is the quadruple factorial number (A007662). 1
 3, 9, 15, 17, 19, 29, 31, 45, 55, 63, 73, 101, 135, 173, 217, 271, 439, 535, 729, 787, 933, 1473, 1651, 6617, 7805, 12461, 13253, 18627, 20243, 55271 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Corresponding primes are: 67, 109, 3529, 10009, 65899, 151412689, 1267389649, ... a(31) > 10^5. Terms > 31 correspond to probable primes. LINKS Henri & Renaud Lifchitz, PRP Records. Search for n!4+64. Joe McLean, Interesting Sources of Probable Primes OpenPFGW Project, Primality Tester EXAMPLE 15!4 + 2^6 = 15*11*7*3*1 + 64 = 3529 is prime, so 15 is in the sequence. MATHEMATICA MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]]; Select[Range[0, 50000], PrimeQ[MultiFactorial[#, 4] + 2^6] &] CROSSREFS Cf. A007662, A037082, A084438, A123910, A242994. Sequence in context: A273323 A061966 A085328 * A062220 A310328 A043381 Adjacent sequences:  A291344 A291345 A291346 * A291348 A291349 A291350 KEYWORD nonn,more AUTHOR Robert Price, Aug 22 2017 EXTENSIONS a(30) from Robert Price, Sep 25 2019 STATUS approved

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Last modified September 18 13:54 EDT 2021. Contains 347527 sequences. (Running on oeis4.)