A076518 Numbers n such that Fibonacci(n) == sigma(n) (mod n).

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

Adjacent sequences: A076515 A076516 A076517 * A076519 A076520 A076521

Keyword

nonn

Author

Joseph L. Pe, Oct 17 2002

Status

approved