A272296 - OEIS

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A272296

Numbers n such that 5^n-4^(n-1) is prime.

0

3, 11, 25, 341, 1827, 2581, 4475, 11157, 41141, 64721

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OFFSET

1,1

COMMENTS

a(11) > 10^5.

LINKS

Table of n, a(n) for n=1..10.

EXAMPLE

3 is a member since 5^3 - 4^2 = 125 - 16 = 109 which is a prime number.

MATHEMATICA

Select[Range[0, 100000], PrimeQ[5^# - 4^(# - 1)] &]

PROG

(PARI) is(n)=ispseudoprime(5^n-4^(n-1)) \\ Charles R Greathouse IV, Jun 13 2017

CROSSREFS

Cf. A093713, A082103, A093717, A093793, A096185, A093794, A093795, A096186, A271883, A271884, A272345.

Sequence in context: A096795 A362176 A160039 * A051925 A211811 A011942

Adjacent sequences: A272293 A272294 A272295 * A272297 A272298 A272299

KEYWORD

nonn,more

AUTHOR

Robert Price, Apr 27 2016

STATUS

approved