A086392 Numbers n such that n/2 is composite and F(n^2+1)==5 (mod n) where F(k) denotes the k-th Fibonacci number.

8, 42, 88, 174, 232, 242, 248, 282, 322, 462, 488, 568, 572, 638, 646, 658, 682, 754, 796, 884, 902, 968, 1266, 1302, 1342, 1562, 1612, 1672, 1722, 1798, 1806, 1974, 1978, 2108, 2158, 2162, 2378, 2542, 2728, 2756, 2886, 3102, 3542, 3638, 3666, 3738, 3782

Offset

1,1

Links

Table of n, a(n) for n=1..47.

Mathematica

Select[Range[4000], CompositeQ[#/2]&&Mod[Fibonacci[#^2+1], #]==5&] (* Harvey P. Dale, Jan 11 2017 *)

Prog

(PARI) isok(n) = !(n%2) && !isprime(n/2) && ((fibonacci(n^2+1) % n) == 5); \\ Michel Marcus, Dec 06 2013

Crossrefs

Cf. A086367.

Sequence in context: A295936 A352397 A204572 * A234860 A292059 A027903

Adjacent sequences: A086389 A086390 A086391 * A086393 A086394 A086395

Keyword

nonn

Author

Benoit Cloitre, Sep 06 2003

Extensions

More terms from Don Reble, Sep 16 2003

More terms from Michel Marcus, Dec 06 2013

Status

approved