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A108098 Numbers a(n) such that there is no k<=2a(n) with a(n)!+k!-1 prime. 0
48, 63, 68, 74, 111, 129, 135, 161, 168, 174, 197, 236, 240, 243, 273, 279, 282, 285, 309, 322, 335, 347, 360, 393, 407, 419, 431, 437, 439, 440, 455, 460, 461, 483, 491, 494, 497, 512, 517, 522, 526, 532, 544, 567, 591, 614, 625, 650, 662, 663, 681, 687 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

For numbers m <= 320 that are not in the sequence, there exists an integer k <= 2m such that m! + k! - 1 is a certified prime. For m > 320 the values of m! + k! - 1 are only probable primes. - Ryan Propper, Sep 02 2005

LINKS

Table of n, a(n) for n=1..52.

MATHEMATICA

Do[l = Range[1, 2*n]; If[Length[Select[l, PrimeQ[n! + #! - 1]&]] == 0, Print[n]], {n, 1, 729}] (Propper)

CROSSREFS

Cf. A075758.

Sequence in context: A080854 A231469 A114821 * A114505 A186400 A205188

Adjacent sequences:  A108095 A108096 A108097 * A108099 A108100 A108101

KEYWORD

nonn

AUTHOR

Ralf Stephan, Jun 01 2005

EXTENSIONS

More terms from Ryan Propper, Sep 02 2005

STATUS

approved

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Last modified October 25 16:45 EDT 2014. Contains 248556 sequences.