A268613 Lucas numbers mod 20.

2, 1, 3, 4, 7, 11, 18, 9, 7, 16, 3, 19, 2, 1, 3, 4, 7, 11, 18, 9, 7, 16, 3, 19, 2, 1, 3, 4, 7, 11, 18, 9, 7, 16, 3, 19, 2, 1, 3, 4, 7, 11, 18, 9, 7, 16, 3, 19, 2, 1, 3, 4, 7, 11, 18, 9, 7, 16, 3, 19, 2, 1, 3, 4, 7, 11, 18, 9, 7, 16, 3, 19, 2, 1, 3, 4, 7, 11, 18, 9, 7, 16, 3, 19, 2, 1, 3, 4, 7, 11, 18, 9, 7, 16, 3, 19, 2, 1, 3, 4, 7, 11

Offset: 0

Author

G. C. Greubel, Feb 08 2016

Keywords

• nonn
• easy

Comments

Sequence of period 12.

This is one of four sequences that are period 12 of the form Lucas[n] Mod x, where x is 8,10,20,40.

Links

• G. C. Greubel, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A000032, A111958, A130893.

Programs

Magma

[Lucas(n) mod 20: n in [0..100]]; // Vincenzo Librandi, Feb 09 2016

Mathematica

Table[Mod[LucasL[n],20],{n,0,100}]
PadRight[{},120,{2,1,3,4,7,11,18,9,7,16,3,19}] (* Harvey P. Dale, Jul 06 2025 *)

Formula

a(n+12) = a(n).