A128162 - OEIS

A128162

a(n) = 3^n modulo Fibonacci(n).

0, 0, 1, 0, 3, 1, 3, 9, 31, 34, 37, 81, 137, 347, 487, 690, 355, 1369, 2001, 1926, 5331, 1369, 4823, 8289, 74043, 77951, 188571, 284781, 490766, 166409, 1333373, 1803615, 1516839, 914943, 3619092, 3987873, 17604245, 8506938, 57277423, 24741861

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OFFSET

1,5

COMMENTS

Numbers k such that a(k) is prime are listed in A128163. Corresponding primes in {a(n)} are {3, 3, 31, 37, 137, 347, 487, 77951, 166409, 13506083561, ...}.

LINKS

Robert Israel, Table of n, a(n) for n = 1..4783

MAPLE

f:= n -> 3 &^ n mod combinat:-fibonacci(n):

map(f, [$1..100]); # Robert Israel, Jul 10 2020

MATHEMATICA

Table[PowerMod[3, n, Fibonacci[n]], {n, 1, 100}]

PROG

(Sage) [power_mod(3, n, fibonacci(n))for n in range(1, 41)] # - Zerinvary Lajos, Nov 28 2009

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

CROSSREFS

Cf. A128163, A128161, A057862 (2^n modulo Fibonacci(n)).