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A076518
Numbers n such that Fibonacci(n) == sigma(n) (mod n).
2
1, 2, 4, 11, 19, 29, 31, 41, 59, 61, 71, 79, 89, 101, 109, 120, 131, 139, 149, 151, 179, 181, 191, 199, 211, 229, 239, 241, 251, 269, 271, 281, 311, 331, 348, 349, 359, 379, 389, 401, 409, 419, 421, 431, 439, 449, 461, 479, 491, 499, 509, 521, 541, 569, 571
OFFSET
1,2
COMMENTS
It appears that most of the terms of this sequence satisfy Fibonacci(n) == 1 (mod n). Also it seems that most of the terms are primes.
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
MATHEMATICA
Select[Range[10^4], Mod[Fibonacci[ # ], # ] == Mod[DivisorSigma[1, # ], # ] &]
PROG
(PARI) fibmod(n, m)=((Mod([1, 1; 1, 0], m))^n)[1, 2]
is(n)=fibmod(n, n)==sigma(n) \\ Charles R Greathouse IV, Nov 27 2016
CROSSREFS
Sequence in context: A288621 A053031 A018674 * A139785 A283173 A283254
KEYWORD
nonn
AUTHOR
Joseph L. Pe, Oct 17 2002
STATUS
approved