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Numbers with 2 zeros in Fibonacci numbers mod m.
21

%I #31 Aug 08 2024 11:07:02

%S 3,6,7,8,9,12,14,15,16,18,20,21,23,24,27,28,30,32,33,35,36,39,40,41,

%T 42,43,45,46,47,48,49,51,52,54,55,56,57,60,63,64,66,67,68,69,70,72,75,

%U 77,78,80,81,82,83,84,86,87,88,90,91,92,93,94,95,96,98,99,100,102,103,104

%N Numbers with 2 zeros in Fibonacci numbers mod m.

%C m is on this list iff m does not have 1 or 4 zeros in the Fibonacci sequence modulo m.

%C A001176(a(n)) = A128924(a(n),1) = 2. - _Reinhard Zumkeller_, Jan 17 2014

%H Reinhard Zumkeller, <a href="/A053030/b053030.txt">Table of n, a(n) for n = 1..10000</a>

%H Brennan Benfield and Oliver Lippard, <a href="https://arxiv.org/abs/2407.20048">Connecting Zeros in Pisano Periods to Prime Factors of K-Fibonacci Numbers</a>, arXiv:2407.20048 [math.NT], 2024. See p. 2.

%H Brennan Benfield and Michelle Manes, <a href="https://arxiv.org/abs/2202.08986">The Fibonacci Sequence is Normal Base 10</a>, arXiv:2202.08986 [math.NT], 2022.

%H M. Renault, <a href="http://webspace.ship.edu/msrenault/fibonacci/fib.htm">Fibonacci sequence modulo m</a>

%o (Haskell)

%o a053030 n = a053030_list !! (n-1)

%o a053030_list = filter ((== 2) . a001176) [1..]

%o -- _Reinhard Zumkeller_, Jan 17 2014

%Y Let {x(n)} be a sequence defined by x(0) = 0, x(1) = 1, x(n+2) = m*x(n+1) + x(n). Let w(k) be the number of zeros in a fundamental period of {x(n)} modulo k.

%Y | m=1 | m=2 | m=3

%Y -----------------------------+----------+---------+---------

%Y The sequence {x(n)} | A000045 | A000129 | A006190

%Y The sequence {w(k)} | A001176 | A214027 | A322906

%Y Primes p such that w(p) = 1 | A112860* | A309580 | A309586

%Y Primes p such that w(p) = 2 | A053027 | A309581 | A309587

%Y Primes p such that w(p) = 4 | A053028 | A261580 | A309588

%Y Numbers k such that w(k) = 1 | A053031 | A309583 | A309591

%Y Numbers k such that w(k) = 2 | this seq | A309584 | A309592

%Y Numbers k such that w(k) = 4 | A053029 | A309585 | A309593

%Y * and also A053032 U {2}

%K nonn

%O 1,1

%A _Henry Bottomley_, Feb 23 2000