

A104217


Period of Perrin (0,2,3,2,5,5,..., A001608) sequence mod n.


4



1, 7, 13, 14, 24, 91, 48, 28, 39, 168, 120, 182, 183, 336, 312, 56, 288, 273, 180, 168, 624, 840, 22, 364, 120, 1281, 117, 336, 871, 2184, 993, 112, 1560, 2016, 48, 546, 1368, 1260, 2379, 168, 1723, 4368, 231, 840, 312, 154, 2257, 728, 336, 840, 3744, 2562
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OFFSET

1,2


COMMENTS

It appears that the n such that n1 divides a(n) is the set of primes of the form x^2+23*y^2 (A033217). The discriminant of the characteristic polynomial of the Perrin sequence is 23.  T. D. Noe, Feb 23 2007


REFERENCES

Analogy to A001175, Pisano periods (or Pisano numbers): period of Fibonacci numbers mod n AND to A046738 for Perrin sequence, where a(n)=a(n2)+a(n3)


LINKS

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


MATHEMATICA

Table[a={0, 2, 3}; a=a0=Mod[a, n]; k=0; While[k++; s=a[[2]]+a[[1]]; a=RotateLeft[a]; a[[ 1]]=Mod[s, n]; a!=a0]; k, {n, 100}]  T. D. Noe, Oct 10 2006


CROSSREFS

Cf. A001175, A046738 and Perrin sequence A001608.
Sequence in context: A275201 A274558 A120100 * A269163 A260482 A191976
Adjacent sequences: A104214 A104215 A104216 * A104218 A104219 A104220


KEYWORD

nonn


AUTHOR

Anthony C Robin, Mar 14 2005


EXTENSIONS

More terms from T. D. Noe, Oct 10 2006


STATUS

approved



