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A143933 a(n)=smallest positive prime x such that x^2-n! is also prime. 2
2, 2, 3, 11, 19, 31, 79, 607, 6337, 4574149, 348776611, 1559776279, 2973510046012997, 16286585271694981, 22869687743093501008057, 142821154179615294686627, 201312988912482288333668455069536465827 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

Every prime which occured in this sequence is bigger as p_n (where p_n is n-th prime) see comment to A121926. For smallest integer numbers x such that x^2-n! is prime see A143931. For smallest prime numbers of the form x^2-n! see A143932.

MATHEMATICA

a = {}; Do[k = Round[Sqrt[n! ]] + 1; While[ ! PrimeQ[k^2 - n! ], k++ ]; If[PrimeQ[k], AppendTo[a, k]], {n, 1, 150}]; a (*Artur Jasinski*)

CROSSREFS

A121926, A143931, A143932

Sequence in context: A067919 A157301 A143931 * A075095 A178343 A156136

Adjacent sequences:  A143930 A143931 A143932 * A143934 A143935 A143936

KEYWORD

nonn

AUTHOR

Artur Jasinski (grafix(AT)csl.pl), Sep 05 2008

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Last modified February 16 16:45 EST 2012. Contains 205938 sequences.