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A086391
Numbers k such that F(k^2+1) == 1 (mod k) where F(k) denotes the k-th Fibonacci number.
2
2, 3, 4, 7, 9, 10, 11, 12, 13, 17, 19, 20, 23, 24, 27, 28, 29, 31, 36, 37, 41, 43, 47, 48, 50, 53, 59, 60, 61, 63, 67, 71, 72, 73, 76, 79, 83, 84, 89, 96, 97, 99, 100, 101, 103, 107, 108, 109, 110, 113, 120, 127, 131, 137, 139, 140, 144, 149, 151, 157, 161, 163, 167, 168
OFFSET
1,1
COMMENTS
Except p=5, all prime numbers p are in the sequence.
LINKS
MATHEMATICA
Select[Range[200], Mod[Fibonacci[#^2 + 1], #] == 1 &] (* Amiram Eldar, May 13 2022 *)
PROG
(PARI) isok(n) = ((fibonacci(n^2+1) % n) == 1); \\ Michel Marcus, Dec 06 2013
CROSSREFS
Sequence in context: A172024 A285500 A119345 * A120127 A047548 A095378
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Sep 06 2003
STATUS
approved