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A071774 Related to Pisano periods: n such that the period of Fibonacci numbers mod n equals 2*(n+1). 5
3, 7, 13, 17, 23, 37, 43, 53, 67, 73, 83, 97, 103, 127, 137, 157, 163, 167, 173, 193, 197, 223, 227, 257, 277, 283, 293, 313, 317, 337, 367, 373, 383, 397, 433, 443, 457, 463, 467, 487, 503, 523, 547, 577, 587, 593, 607, 613, 617, 643, 647, 653, 673, 683, 727 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Terms are primes with final digit 3 or 7.

LINKS

Table of n, a(n) for n=1..55.

PROG

(PARI) for(n=2, 5000, t=2*(n+1); good=1; if(fibonacci(t)%n==0, for(s=0, t, if(fibonacci(t+s)%n!=fibonacci(s)%n, good=0; break); if(s>1&&s<t-1&&fibonacci(s)%n==0, cur=s; good2=1; for(ss=0, s, if(fibonacci(ss+s)%n!=fibonacci(ss)%n, good2=0; break)); if(good2, good=0; break); ); ); if(good, print1(n, ", ")))) (Klasen)

(PARI) forprime(p=3, 3000, if(p%5==2||p%5==3, a=1; b=0; c=1; while(a!=0||b!=1, c++; d=a; a=b; a=(a+d)%p; b=d%p); if(c==(2*(p+1)), print1(p", ")))) /* V. Raman, Nov 22 2012 */

CROSSREFS

Cf. A001175, A060305, A071776.

Cf. A216067.

Sequence in context: A034913 A040148 A097957 * A019403 A045422 A191071

Adjacent sequences:  A071771 A071772 A071773 * A071775 A071776 A071777

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Jun 04 2002

EXTENSIONS

More terms from Lambert Klasen (Lambert.Klasen(AT)gmx.net), Dec 21 2004

STATUS

approved

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Last modified September 25 12:53 EDT 2017. Contains 292469 sequences.