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A086390
Composite n such that F(n^2+1)==1 (mod n) where F(k) denotes the k-th Fibonacci number.
0
4, 9, 10, 12, 20, 24, 27, 28, 36, 48, 50, 60, 63, 72, 76, 84, 96, 99, 100, 108, 110, 120, 140, 144, 161, 168, 180, 192, 196, 204, 216, 220, 228, 231, 240, 250, 252, 276, 288, 300, 323, 324, 336, 341, 351, 360, 364, 369, 377, 384, 408, 420, 432, 451, 456, 480
OFFSET
1,1
MATHEMATICA
Select[Range[500], CompositeQ[#]&&Mod[Fibonacci[#^2+1], #]==1&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 03 2020 *)
PROG
(PARI) isok(n) = !isprime(n) && ((fibonacci(n^2+1) % n) == 1); \\ Michel Marcus, Dec 06 2013
CROSSREFS
Cf. A086367.
Subsequence of A086391.
Sequence in context: A243194 A342393 A283320 * A038029 A197039 A020672
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Sep 06 2003
STATUS
approved