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A128163 a(n) = numbers n such that 3^n modulo Fibonacci(n) is prime, or A128162(n) is prime. 2
5, 7, 9, 11, 13, 14, 15, 26, 30, 53, 66, 82, 155, 189, 225, 261, 625, 870, 1071, 7655, 8191, 8883, 9226, 12246, 70274, 71595 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Corresponding primes in A128162(n) are {3,3,31,37,137,347,487,77951,166409,13506083561,...}.

LINKS

Table of n, a(n) for n=1..26.

MATHEMATICA

Do[f=PowerMod[3, n, Fibonacci[n]]; If[PrimeQ[f], Print[{n, f}]], {n, 1, 1071}]

PROG

(PARI) is(n)=ispseudoprime(3^n%fibonacci(n)) \\ Charles R Greathouse IV, Jun 19 2017

(PFGW)

ABC2 3^$a % F($a)

a: from 5 to 1000000

// Charles R Greathouse IV, Jun 19 2017

CROSSREFS

Cf. A128162 = 3^n modulo Fibonacci(n). Cf. A128161, A057862 = 2^n modulo Fibonacci(n).

Sequence in context: A175382 A279244 A325797 * A177088 A168146 A106505

Adjacent sequences:  A128160 A128161 A128162 * A128164 A128165 A128166

KEYWORD

hard,more,nonn

AUTHOR

Alexander Adamchuk, Feb 19 2007

EXTENSIONS

Corrected and extended by Stefan Steinerberger, Jun 10 2007

a(25)-a(26) from Donovan Johnson, Sep 03 2008

STATUS

approved

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Last modified July 20 11:28 EDT 2019. Contains 325180 sequences. (Running on oeis4.)