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A300477 Number of positive integers k with 1 < k < n such that n^k + k^n is prime. 2
0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

2

COMMENTS

a(n) > 0 iff n is a term of A162488.

a(n) > 1 iff n is a term of A300478.

LINKS

Robert Israel, Table of n, a(n) for n = 2..1940

MAPLE

f:= n -> nops(select(isprime, [seq(n^k-k^n, k=2..n-1)])):

map(f, [$2..100]); # Robert Israel, Sep 24 2020

PROG

(PARI) a(n) = my(i=0); for(k=2, n-1, if(ispseudoprime(n^k+k^n), i++)); i

CROSSREFS

Cf. A162488, A300478.

Sequence in context: A025464 A162518 A330306 * A228495 A284683 A288673

Adjacent sequences:  A300474 A300475 A300476 * A300478 A300479 A300480

KEYWORD

nonn

AUTHOR

Felix Fröhlich, Mar 06 2018

STATUS

approved

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Last modified January 18 06:47 EST 2022. Contains 350452 sequences. (Running on oeis4.)