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A106307
Primes that yield a simple orbit structure in 3-step recursions.
2
3, 5, 23, 31, 37, 59, 67, 71, 89, 97, 103, 113, 137, 157, 179, 181, 191, 223, 229, 251, 313, 317, 331, 353, 367, 379, 383, 389, 433, 443, 449, 463, 467, 487, 509, 521, 577, 587, 619, 631, 641, 643, 647, 653, 661, 691, 709, 719, 727, 751, 797, 823, 829
OFFSET
1,1
COMMENTS
Consider the 3-step recursion x(k)=x(k-1)+x(k-2)+x(k-3) mod n. For any of the n^3 initial conditions x(1), x(2) and x(3) in Zn, the recursion has a finite period. When n is a prime in this sequence, all of the orbits, except the one containing (0,0,0), have the same length.
A prime p is in this sequence if either (1) the polynomial x^3-x^2-x-1 mod p has no zeros for x in [0,p-1] (see A106282) or (2) the polynomial has zeros, but none is a root of unity mod p. The first two primes in the second category are 103 and 587.
LINKS
Eric Weisstein's World of Mathematics, Fibonacci n-Step Number.
CROSSREFS
Cf. A106285 (orbits of 3-step sequences).
Sequence in context: A136891 A296920 A106857 * A106282 A163153 A339414
KEYWORD
nonn
AUTHOR
T. D. Noe, May 02 2005, revised May 12 2005
STATUS
approved