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%I #17 Jun 13 2021 10:20:53
%S 5,7,9,11,13,14,15,26,30,53,66,82,155,189,225,261,625,870,1071,7655,
%T 8191,8883,9226,12246,70274,71595
%N Numbers k such that A128162(k) is prime.
%C Corresponding primes in A128162 are {3, 3, 31, 37, 137, 347, 487, 77951, 166409, 13506083561, ...}.
%t Do[f=PowerMod[3,n,Fibonacci[n]];If[PrimeQ[f],Print[{n,f}]],{n,1,1071}]
%t Select[Range[72000],PrimeQ[PowerMod[3,#,Fibonacci[#]]]&] (* _Harvey P. Dale_, Sep 11 2019 *)
%o (PARI) is(n)=ispseudoprime(3^n%fibonacci(n)) \\ _Charles R Greathouse IV_, Jun 19 2017
%o (PFGW)
%o ABC2 3^$a % F($a)
%o a: from 5 to 1000000
%o // _Charles R Greathouse IV_, Jun 19 2017
%Y Cf. A128162 (3^n modulo Fibonacci(n)), A128161, A057862 (2^n modulo Fibonacci(n)).
%K hard,more,nonn
%O 1,1
%A _Alexander Adamchuk_, Feb 19 2007
%E Corrected and extended by _Stefan Steinerberger_, Jun 10 2007
%E a(25)-a(26) from _Donovan Johnson_, Sep 03 2008
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