OFFSET
1,4
COMMENTS
LINKS
T. D. Noe, Table of n, a(n) for n=1..10000
E. L. Blanton, Jr., S. P. Hurd and J. S. McCranie, On a digraph defined by squaring modulo n, Fibonacci Quart. 30 (Nov. 1992), 322-333.
Haifeng Xu, The largest cycles consist by the quadratic residues and Fermat primes, arXiv:1601.06509 [math.NT], 2016. See table on page 2.
FORMULA
MATHEMATICA
a[n_] := Module[{p = Prime[n], k}, k = (p-1)/2^IntegerExponent[p-1, 2]; MultiplicativeOrder[2, k]]; Array[a, 100] (* Jean-François Alcover, Jan 28 2016, after T. D. Noe *)
PROG
(PARI) a(n) = {ppn = prime(n) - 1; k = ppn >> valuation(ppn, 2); znorder(Mod(2, k)); } \\ Michel Marcus, Nov 11 2015
(PARI) rpsi(n) = lcm(znstar(n)[2]); \\ A002322
pb(n) = znorder(Mod(2, n/2^valuation(n, 2))); \\ A007733
a(n) = pb(rpsi(prime(n))); \\ Michel Marcus, Jan 28 2016
CROSSREFS
KEYWORD
nonn,changed
AUTHOR
STATUS
approved