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A175181 Pisano period length of the 2-Fibonacci numbers A000129. 26
1, 2, 8, 4, 12, 8, 6, 8, 24, 12, 24, 8, 28, 6, 24, 16, 16, 24, 40, 12, 24, 24, 22, 8, 60, 28, 72, 12, 20, 24, 30, 32, 24, 16, 12, 24, 76, 40, 56, 24, 10, 24, 88, 24, 24, 22, 46, 16, 42, 60, 16, 28, 108, 72, 24, 24, 40, 20, 40, 24, 124, 30, 24, 64, 84, 24, 136 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Period length of the sequence defined by reading A000129 modulo n.

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000

S. Falcon and A. Plaza, k-Fibonacci sequences modulo m, Chaos, Solit. Fractals 41 (2009), 497-504.

Eric Weisstein's World of Mathematics, Pisano period.

Wikipedia, Pisano period.

MAPLE

F := proc(k, n) option remember; if n <= 1 then n; else k*procname(k, n-1)+procname(k, n-2) ; end if; end proc:

Pper := proc(k, m) local cha, zer, n, fmodm ; cha := [] ; zer := [] ; for n from 0 do fmodm := F(k, n) mod m ; cha := [op(cha), fmodm] ; if fmodm = 0 then zer := [op(zer), n] ; end if; if nops(zer) = 5 then break; end if; end do ; if [op(1..zer[2], cha) ] = [ op(zer[2]+1..zer[3], cha) ] and [op(1..zer[2], cha)] = [ op(zer[3]+1..zer[4], cha) ] and [op(1..zer[2], cha)] = [ op(zer[4]+1..zer[5], cha) ] then return zer[2] ; elif [op(1..zer[3], cha) ] = [ op(zer[3]+1..zer[5], cha) ] then return zer[3] ; else return zer[5] ; end if; end proc:

k := 2 ; seq( Pper(k, m), m=1..80) ;

MATHEMATICA

Table[s = t = Mod[{0, 1}, n]; cnt = 1; While[tmp = Mod[2*t[[2]] + t[[1]], n]; t[[1]] = t[[2]]; t[[2]] = tmp; s != t, cnt++]; cnt, {n, 100}] (* T. D. Noe, Jul 09 2012 *)

CROSSREFS

Cf. A000129, A001175, A175182, A175183, A175184, A175185.

Sequence in context: A334447 A192034 A209874 * A110003 A035302 A104772

Adjacent sequences:  A175178 A175179 A175180 * A175182 A175183 A175184

KEYWORD

nonn

AUTHOR

R. J. Mathar, Mar 01 2010

STATUS

approved

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Last modified March 9 03:00 EST 2021. Contains 341961 sequences. (Running on oeis4.)