

A231958


Numbers n dividing the Lucas sequence u(n) defined by u(i) = 2*u(i1)  5*u(i2) with initial conditions u(0)=0, u(1)=1


0



1, 2, 4, 8, 12, 16, 24, 32, 36, 48, 56, 64, 72, 96, 108, 112, 128, 132, 144, 156, 168, 192, 216, 224, 256, 264, 272, 288, 312, 324, 336, 384, 392, 396, 432, 448, 468, 496, 504, 512, 528, 544, 552, 576, 624, 648, 672, 768, 784, 792, 816, 864, 896, 936, 972
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OFFSET

1,2


COMMENTS

All terms except 1 and 2 are divisible by 4. The sequence contains every nonnegative integer power of 2. There are infinitely many multiples of 12 in the sequence.


LINKS

Table of n, a(n) for n=1..55.
C. Smyth, The Terms in Lucas Sequences Divisible by their Indices, Journal of Integer Sequences, Vol.13 (2010), Article 10.2.4.


MATHEMATICA

nn = 2000; s = LinearRecurrence[{2, 5}, {1, 2}, nn]; t = {}; Do[If[Mod[s[[n]], n] == 0, AppendTo[t, n]], {n, nn}]; t (* T. D. Noe, Nov 20 2013 *)


CROSSREFS

Cf. A000079 (powers of 2 (subsequence)).
Cf. A045873 (Lucas sequence).
Sequence in context: A324174 A047836 A325762 * A227730 A246692 A181824
Adjacent sequences: A231955 A231956 A231957 * A231959 A231960 A231961


KEYWORD

nonn,easy


AUTHOR

Thomas M. Bridge, Nov 15 2013


STATUS

approved



