A279072 Numbers k such that Fibonacci(k) == +-1 (mod k) and k is neither 1 nor prime nor twice a prime.

323, 572, 646, 754, 2737, 3782, 4181, 5474, 5777, 6479, 6721, 7654, 7743, 8362, 10877, 11554, 11663, 12958, 13201, 13202, 13442, 15251, 16298, 17261, 17302, 18407, 19043, 21754, 23042, 23326, 23407, 26402, 26978, 27071, 27962, 30502, 34238, 34561, 34943, 35207

Offset

1,1

Comments

Included among the 313 terms less than 10^6 in this sequence are 70 semiprimes, among which are 9 twin prime products (323=17*19, 11663=107*109, 19043=137*139, 39203=197*199, 51983=227*229, 121103=347*349, 381923=617*619, 685583=827*829, 736163=857*859), 8 of the form p(2p+3) (5777=53*109, 10877=73*149, 75077=193*389, 100127=223*449, 161027=283*569, 430127=463*929, 635627=563*1129), and 4 of the form p(3p-2) (97921=181*541, 556421=431*1291, 636641=461*1381, 722261=491*1471).

Links

Giovanni Resta, Table of n, a(n) for n = 1..10000

Example

323 is in the sequence because Fibonacci(323) mod 323 = 1.
646 (=2*323) is in the sequence because Fibonacci(646) mod 646 = 645 and 645 == -1 (mod 646).

Crossrefs

Cf. A000045, A279071.

Sequence in context: A182504 A177745 A065822 * A158306 A257973 A083138

Adjacent sequences: A279069 A279070 A279071 * A279073 A279074 A279075

Keyword

nonn

Author

Jon E. Schoenfield, Dec 30 2016

Status

approved