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A253968 Numbers n such that (23*10^n - 26)/6 is prime. 1
2, 4, 6, 10, 11, 18, 29, 151, 920, 1456, 1716, 1915, 4148, 4403, 8005, 9600, 41945, 47238 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..18.

EXAMPLE

n = 2, 4, and 6, yield (23*10^n - 26)/6 = 379, 38329, and 3833329, respectively, which are prime.

MATHEMATICA

fQ[n_] := PrimeQ[(23*10^n - 26)/6]; Select[ Range@ 10000, fQ] (* Robert G. Wilson v, Jan 28 2015 *)

PROG

(PARI) is(n)=ispseudoprime((23*10^n-26)/6) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Cf. A254005.

Sequence in context: A027435 A014666 A067852 * A102025 A226295 A090127

Adjacent sequences:  A253965 A253966 A253967 * A253969 A253970 A253971

KEYWORD

nonn,more

AUTHOR

Hans Havermann, Jan 24 2015

STATUS

approved

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Last modified April 19 18:34 EDT 2019. Contains 322286 sequences. (Running on oeis4.)