A182425 - OEIS

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A182425

a(n) the largest integer K such that (prime(n+1)-1)^(2^k)+1 for 0<=k<=K is prime.

4, 3, 2, 1, 0, 2, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 2, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 1, 2, 0, 0, 0, 0, 0

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OFFSET

1,1

COMMENTS

This sequence is a generalized reference to Fermat primes.

LINKS

Table of n, a(n) for n=1..87.

MATHEMATICA

Table[k = 0; While[PrimeQ[(Prime[n+1] - 1)^(2^k) + 1], k++]; k - 1, {n, 100}] (* T. D. Noe, Apr 28 2012 *)

CROSSREFS

Cf. A182199.

Sequence in context: A023446 A258447 A066440 * A071692 A378371 A307335

Adjacent sequences: A182422 A182423 A182424 * A182426 A182427 A182428

KEYWORD

nonn

AUTHOR

Thomas Ordowski, Apr 28 2012

STATUS

approved