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 A204661 Numbers n such that n!8+1 is prime (for n!8 see A114800). 8
 0, 1, 2, 4, 6, 28, 30, 46, 60, 72, 86, 90, 112, 154, 162, 206, 280, 354, 400, 512, 606, 614, 678, 790, 938, 1054, 1092, 1148, 1582, 1788, 2088, 2206, 2598, 2912, 3672, 4642, 6272, 6428, 7084, 7604, 8580, 9464, 12762, 18386, 24910, 30448, 31696, 40288, 41682, 45730 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS n!8 = A114800(n). No other terms < 50000. - Robert Price, Jul 29 2012 LINKS Ken Davis, Status of Search for Multifactorial Primes. Ken Davis, Results for n!8+1. MATHEMATICA MultiFactorial[n_, k_] := If[n < 1, 1, n*MultiFactorial[n - k, k]]; Select[Range[0, 1000], PrimeQ[MultiFactorial[#, 8] + 1] & ] (* Robert Price, Apr 19 2019 *) PROG (PARI) for(n=0, 9999, isprime(prod(i=0, (n-2)\8, n-8*i)+1)& print1(n", ")) CROSSREFS Cf. A204657, A204658, A204659, A204660, A204662, A204663, A204664, A156165, A156167, A085150, A085148, A085146, A037083, A080778, A002981. Sequence in context: A318609 A195333 A106274 * A284919 A279419 A077633 Adjacent sequences:  A204658 A204659 A204660 * A204662 A204663 A204664 KEYWORD nonn,hard AUTHOR M. F. Hasler, Jan 17 2012 EXTENSIONS a(35)-a(50) from Robert Price, Jul 29 2012 STATUS approved

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Last modified July 26 14:45 EDT 2021. Contains 346294 sequences. (Running on oeis4.)