|
|
A023175
|
|
Numbers k such that Fibonacci(k) == 3 (mod k).
|
|
1
|
|
|
1, 2, 4, 76, 124, 196, 244, 316, 374, 436, 556, 604, 724, 796, 844, 916, 964, 1084, 1324, 1396, 1516, 1636, 1684, 1756, 1768, 1804, 1996, 2164, 2284, 2404, 2476, 2524, 2644, 2764, 2836, 2956, 3004, 3076, 3244, 3316, 3436, 3676, 3964, 4036, 4084, 4156, 4204
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
Among the first 10000 terms, all are even except for 1 and 20017. - Robert Israel, Sep 22 2023
Contains k if k == 4 (mod A001175(k)). In particular, this is the case if k = 4 * p where p is a prime == 1 or 19 (mod 30). Most terms appear to be of this type, including all but 141 of the first 10000 terms. - Robert Israel, Sep 24 2023
|
|
LINKS
|
|
|
MAPLE
|
filter:= proc(n) uses LinearAlgebra:-Modular; local A;
A:= Mod(n, Matrix([[0, 1], [1, 1]]), integer[]);
MatrixPower(n, A, n)[1, 2] - 3 mod n = 0
end proc:
filter(1):= true:
|
|
MATHEMATICA
|
Select[Table[{p, Fibonacci[p]}, {p, 4500}], Mod[Last[#]-3, First[#]]==0&][[All, 1]] (* Harvey P. Dale, Sep 22 2021 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|