A128924 T(n,m) is the number of m's in the fundamental period of Fibonacci numbers mod n.

1, 1, 2, 2, 3, 3, 1, 3, 1, 1, 4, 4, 4, 4, 4, 2, 6, 3, 4, 3, 6, 2, 4, 2, 1, 1, 2, 4, 2, 3, 2, 1, 0, 3, 0, 1, 2, 5, 2, 2, 2, 2, 2, 2, 5, 4, 8, 4, 8, 4, 8, 4, 8, 4, 8, 1, 3, 2, 1, 0, 1, 0, 0, 1, 0, 1, 2, 5, 2, 2, 1, 5, 0, 1, 1, 2, 2, 1, 4, 4, 2, 2, 0, 4, 0, 0, 4, 0, 2, 2, 4, 2, 8, 2, 2, 1, 4, 4, 4, 4, 4, 1, 2, 2, 8

Offset: 1

Author

R. J. Mathar, Apr 25 2007

Keywords

• nonn
• tabl

Comments

T(n,m) is the triangle read by rows, 0<=m

A118965 and A066853 give numbers of zeros and nonzeros in n-th row, respectively. - Reinhard Zumkeller, Jan 16 2014

Examples

			{F(k) mod 4} has fundamental period (0,1,1,2,3,1), see A079343, with
T(4,0)=1 zero, T(4,1)=3 ones, T(4,2)=1 two's, T(4,3)=1 three's. The triangle starts
1,
1, 2,
2, 3, 3,
1, 3, 1, 1,
4, 4, 4, 4, 4,
2, 6, 3, 4, 3, 6,
2, 4, 2, 1, 1, 2, 4,
2, 3, 2, 1, 0, 3, 0, 1,
2, 5, 2, 2, 2, 2, 2, 2, 5,
4, 8, 4, 8, 4, 8, 4, 8, 4, 8,
1, 3, 2, 1, 0, 1, 0, 0, 1, 0, 1,
2, 5, 2, 2, 1, 5, 0, 1, 1, 2, 2, 1,
4, 4, 2, 2, 0, 4, 0, 0, 4, 0, 2, 2, 4,
2, 8, 2, 2, 1, 4, 4, 4, 4, 4, 1, 2, 2, 8,
2, 3, 3, 2, 3, 3, 2, 3, 3, 2, 3, 3, 2, 3, 3,
2, 3, 4, 1, 0, 3, 0, 1, 2, 3, 0, 1, 0, 3, 0, 1,
4, 4, 2, 2, 4, 2, 0, 0, 2, 2, 0, 0, 2, 4, 2, 2, 4,
		

Links

• Reinhard Zumkeller, Rows n = 1..125 of triangle, flattened
• G. Darvasi and St. Eckmann, Zur Verteilung der Reste der Fibonacci-Folge modulo 5c, Elemente der Mathematik 50 (1995) pp. 76-80.

Crossrefs

Cf. A053029, A053030, A053031, A001175 (row sums), A001176 (1st column).

Programs

Haskell

import Data.List (group, sort)
a128924 n k = a128924_tabl !! (n-1) !! (k-1)
a128924_tabl = map a128924_row [1..]
a128924_row 1 = [1]
a128924_row n = f [0..n-1] $ group $ sort $ g 1 ps where
   f []     _                            = []
   f (v:vs) wss'@(ws:wss) | head ws == v = length ws : f vs wss
                          | otherwise    = 0 : f vs wss'
   g 0 (1 : xs) = []
   g _ (x : xs) = x : g x xs
   ps = 1 : 1 : zipWith (\u v -> (u + v) `mod` n) (tail ps) ps
-- Reinhard Zumkeller, Jan 16 2014

Maple

A128924 := proc(m,h)
    local resul,k,M ;
    resul :=0 ;
    for k from 0 to A001175(m)-1 do
        M := combinat[fibonacci](k) mod m ;
        if M = h then
            resul := resul+1 ;
        end if ;
    end do;
    resul ;
end proc:
seq(seq(A128924(m,h),h=0..m-1),m=1..17) ;

Mathematica

A001175[1] = 1; A001175[n_] := For[k = 1, True, k++, If[Mod[Fibonacci[k], n] == 0 && Mod[Fibonacci[k+1], n] == 1, Return[k]]]; T[m_, h_] := Module[{resul, k, M}, resul = 0; For[k = 0, k <= A001175[m]-1, k++, M = Mod[Fibonacci[k], m]; If[ M == h, resul++]]; Return[resul]]; Table[T[m, h], {m, 1, 17}, {h, 0, m-1}] // Flatten (* Jean-François Alcover, Feb 11 2015, after Maple code *)

Formula

T(n,n) = A235715(n). - Reinhard Zumkeller, Jan 17 2014

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