

A253806


One half of the maximal values of the length of the period for Fibonacci numbers modulo p (A001175(p)) for primes p > 5, according to Wall's Theorems 6 and 7.


1



8, 5, 14, 18, 9, 24, 14, 15, 38, 20, 44, 48, 54, 29, 30, 68, 35, 74, 39, 84, 44, 98, 50, 104, 108, 54, 114, 128, 65, 138, 69, 74, 75, 158, 164, 168, 174
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OFFSET

1,1


LINKS

Table of n, a(n) for n=1..37.
D. D. Wall, Fibonacci series modulo m, Amer. Math. Monthly, 67 (1960), 525532.


FORMULA

a(n) = (prime(n+3)  1)/2 if prime(n+3) == 1 or 9 (mod 10) and a(n) = (prime(n+3) + 1) if
prime(n+3) == 3 or 7 (mod 10), n >= 1.


EXAMPLE

a(1) = 8 = 7 + 1 because prime(4) = 7 == 7 (mod 10). The length of the period for 7 is 2*8 = 16 = A001175(7).
a(2) = 5 = (11  1)/2 because prime(4) = 11 = 1 (mod 10). The length of the period for 11 is 10 = A001175(11).


CROSSREFS

Cf. A001175, A222413, A222414.
Sequence in context: A087462 A168204 A193681 * A199806 A070484 A096480
Adjacent sequences: A253803 A253804 A253805 * A253807 A253808 A253809


KEYWORD

nonn,easy


AUTHOR

Wolfdieter Lang, Jan 16 2015


STATUS

approved



