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A302088 Numbers k such that 5*k^k + 4 is prime. 2
3, 5, 9, 183, 561 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Next term, if it exists, is greater than 5000.

LINKS

Table of n, a(n) for n=1..5.

MATHEMATICA

Select[Range[1, 1000], PrimeQ[5*#^# + 4] &] (* Vaclav Kotesovec, Apr 01 2018 *)

PROG

(PARI) for(n=0, 500, if(isprime(5*n^n+4), print1(n", ")))

(PARI) lista(nn) = forstep(n=1, nn, 2, if(ispseudoprime(5*n^n+4), print1(n, ", "))); \\ Altug Alkan, Apr 01 2018

CROSSREFS

Numbers k such that b*k^k + b - 1 is prime: A110932 (b=2), A160360 (b=3), A301520 (b=4), this sequence (b=5), A302090 (b=6).

Cf. A302089.

Sequence in context: A121622 A188983 A083519 * A211414 A173706 A332359

Adjacent sequences:  A302085 A302086 A302087 * A302089 A302090 A302091

KEYWORD

nonn,more,hard

AUTHOR

Seiichi Manyama, Apr 01 2018

EXTENSIONS

a(5) from Vaclav Kotesovec, Apr 01 2018

STATUS

approved

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Last modified December 2 20:25 EST 2021. Contains 349445 sequences. (Running on oeis4.)