OFFSET
0,2
COMMENTS
Period 9: repeat (1,4,16,7,9,17,11,6,5).
Also continued fraction expansion of (13140908+sqrt(323139488118562))/24969762. - Bruno Berselli, Sep 09 2011
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,0,1).
FORMULA
a(n+9) = a(n).
G.f.: (1 + 4*x + 16*x^2 + 7*x^3 + 9*x^4 + 17*x^5 + 11*x^6 + 6*x^7 + 5*x^8)/((1-x)*(1+x+x^2)*(1+x^3+x^6)). - Bruno Berselli, Sep 09 2011
MATHEMATICA
PowerMod[4, Range[0, 100], 19] (* or *)
PadRight[{}, 100, {1, 4, 16, 7, 9, 17, 11, 6, 5}] (* Paolo Xausa, Mar 17 2024 *)
PROG
(Magma) [4^n mod 19 : n in [0..80]]; // Vincenzo Librandi, Sep 09 2011
(PARI) a(n)=lift(Mod(4, 19)^n) \\ Charles R Greathouse IV, Mar 22 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
M. F. Hasler, Mar 10 2011
STATUS
approved