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A253380 Numbers n such that 17^n+4 is prime. 0
0, 2, 6, 18, 7238 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

No further terms up to 10000.

LINKS

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

EXAMPLE

For n = 0: 17^0+4 = 5, which is prime, so 0 is a term of the sequence.

For n = 2: 17^2+4 = 293, which is prime, so 2 is a term of the sequence.

MATHEMATICA

Select[Range@10^5, PrimeQ[17^# + 4] &] (* Michael De Vlieger, Jan 03 2015 *)

PROG

(PARI) for(n=0, 1e5, if(ispseudoprime(17^n+4), print1(n, ", ")))

CROSSREFS

Corresponding sequences for k^n+4: A058958 (k=3), A124621 (k=5), A096305(k=7), A217384 (k=9), A137236 (k=13), A247166 (k=15), A243397 (k=19).

Sequence in context: A064535 A240643 A262971 * A128123 A227884 A186769

Adjacent sequences:  A253377 A253378 A253379 * A253381 A253382 A253383

KEYWORD

nonn,more

AUTHOR

Felix Fröhlich, Dec 31 2014

STATUS

approved

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Last modified June 14 05:51 EDT 2021. Contains 345018 sequences. (Running on oeis4.)