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A300478 Numbers n where more than one positive integer k with 1 < k < n exists such that n^k + k^n is prime. 1
114, 318, 590, 790, 903, 1036, 1158, 1263, 1298, 1545, 1588 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numbers n such that A300477(n) > 1.

Subsequence of A162488.

LINKS

Table of n, a(n) for n=1..11.

EXAMPLE

114 is a term of the sequence, since 114^k + k^114 is prime for two values of k with 1 < k < 114, namely, k=67 and k=97.

PROG

(PARI) a300477(n) = my(i=0); for(k=2, n-1, if(ispseudoprime(n^k+k^n), i++)); i

is(n) = a300477(n) > 1

CROSSREFS

Cf. A162488, A300477.

Sequence in context: A171374 A228962 A250725 * A305066 A322541 A323758

Adjacent sequences:  A300475 A300476 A300477 * A300479 A300480 A300481

KEYWORD

nonn,hard,more

AUTHOR

Felix Fröhlich, Mar 06 2018

EXTENSIONS

a(7)-a(11) from Robert Israel, Sep 25 2020

STATUS

approved

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Last modified May 28 16:37 EDT 2022. Contains 354119 sequences. (Running on oeis4.)