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A258452 Numbers n such that n!! - 512 is prime. 4
9, 11, 21, 23, 45, 65, 79, 153, 155, 199, 361, 799, 883, 1237, 1253, 1753, 4975, 5117, 5843, 8179, 12831 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Corresponding primes are 433, 9883, 13749310063, 316234142713, ... .

a(22) > 50000.

LINKS

Table of n, a(n) for n=1..21.

Joe McLean, Interesting Sources of Probable Primes

MATHEMATICA

Select[Range[0, 50000], If[#!! - 512 > 0, PrimeQ[#!! - 512]] &]

PROG

(PARI) for(n=1, 1e4, if (ispseudoprime(m=prod(k=0, (n-1)\2, n - 2*k) - 512), print1(n", "))) \\ Altug Alkan, Nov 06 2015

CROSSREFS

Cf. A006882, A007749, A094144, A123910, A258616, A262772.

Sequence in context: A284294 A195572 A046259 * A299250 A074345 A022323

Adjacent sequences:  A258449 A258450 A258451 * A258453 A258454 A258455

KEYWORD

hard,more,nonn

AUTHOR

Robert Price, Nov 05 2015

STATUS

approved

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Last modified August 17 16:57 EDT 2019. Contains 326059 sequences. (Running on oeis4.)