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 A128161 Numbers k such that 2^k modulo Fibonacci(k) is prime, i.e., A057862(k) is prime. 2
 5, 7, 9, 13, 14, 19, 25, 88, 100, 113, 130, 440, 503, 2800, 3203, 3346, 4357, 6496, 8822, 16316, 20039, 22381, 30481, 33779, 71864, 110390, 127796, 441190, 457249 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Corresponding primes in A057862 are {2, 11, 2, 37, 173, 1663, 18257, 447876604131364627, 55437674149894825801, ...}. LINKS MAPLE select(n->isprime(2 &^n mod combinat:-fibonacci(n)), [\$1..3000]); # Muniru A Asiru, Jul 17 2018 MATHEMATICA Do[f=PowerMod[2, n, Fibonacci[n]]; If[PrimeQ[f], Print[{n, f}]], {n, 1, 503}] PROG (PARI) is(n)=ispseudoprime(2^n%fibonacci(n)) \\ Charles R Greathouse IV, Jun 19 2017 (PFGW) ABC2 2^\$a % F(\$a) a: from 5 to 1000000 // Charles R Greathouse IV, Jun 19 2017 CROSSREFS Cf. A057862 = 2^n modulo Fibonacci(n). Cf. A128162, A128163. Sequence in context: A115913 A200268 A251627 * A141106 A047478 A048974 Adjacent sequences: A128158 A128159 A128160 * A128162 A128163 A128164 KEYWORD hard,more,nonn AUTHOR Alexander Adamchuk, Feb 19 2007 EXTENSIONS a(14)-a(19) from Stefan Steinerberger, Jun 10 2007 More terms from Ryan Propper, Jan 11 2008 a(25)-a(26) from Donovan Johnson, Sep 03 2008 a(27) from Charles R Greathouse IV, Jun 20 2017 a(28)-a(29) from Charles R Greathouse IV, Jun 30 2017 STATUS approved

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Last modified December 5 18:02 EST 2022. Contains 358588 sequences. (Running on oeis4.)