login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A071776
Related to Pisano periods: n such that the period of Fibonacci numbers mod n equals 3*(n+2).
3
6, 14, 26, 74, 86, 134, 146, 194, 206, 254, 314, 326, 386, 446, 554, 566, 626, 674, 734, 746, 794, 866, 914, 926, 974, 1046, 1094, 1154, 1214, 1226, 1286, 1346, 1454, 1466, 1514, 1574, 1646, 1706, 1754, 1766, 1814, 1874, 1994, 2066, 2126, 2186, 2234, 2246
OFFSET
1,1
COMMENTS
a(n)/2 are primes with final digit 3 or 7 among primes in a related sequence: "m such that the period of Fibonacci numbers mod m equals 2*(m+1)".
PROG
(PARI) for(n=2, 4000, t=3*(n+2); 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)
CROSSREFS
Sequence in context: A168648 A093776 A107317 * A063590 A349723 A378230
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