A087347 Numbers k that divide Sum_{j=1..k} Fibonacci(j*k).

1, 2, 5, 8, 12, 15, 20, 24, 25, 32, 36, 44, 48, 50, 56, 60, 63, 72, 80, 84, 95, 96, 104, 108, 110, 120, 125, 128, 135, 140, 144, 152, 155, 168, 175, 180, 185, 192, 200, 204, 207, 209, 216, 224, 228, 240, 252, 264, 276, 279, 288, 300, 320, 323, 324, 336, 360, 368

Offset

1,2

Links

Vaclav Kotesovec, Table of n, a(n) for n = 1..184

Vaclav Kotesovec, Plot of a(n)/(n*log(n)) for n = 2..184

Formula

Conjecture: a(n) is asymptotic to c*n*log(n) with c around 1.3. [This conjecture is probably false, see plot. - Vaclav Kotesovec, Feb 16 2019]

Mathematica

Select[Range[380], Divisible[Sum[Fibonacci[# k], {k, #}], #]&] (* Harvey P. Dale, Aug 16 2011 *)

Crossrefs

Sequence in context: A080753 A248184 A156745 * A062468 A365624 A228153

Adjacent sequences: A087344 A087345 A087346 * A087348 A087349 A087350

Keyword

nonn

Author

Benoit Cloitre, Oct 20 2003

Extensions

More terms from Ray Chandler, Oct 22 2003

Status

approved