OFFSET
0,2
COMMENTS
Period 4: repeat [1, 4, 16, 13].
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,0,0,1).
FORMULA
G.f.: (1+4*x+16*x^2+13*x^3)/(1-x^4).
a(n) = a(n-4) for n>3.
From Wesley Ivan Hurt, Jun 29 2016: (Start)
a(n) = (34 - 3*(5 + 3*I)*I^(-n) - 3*(5 - 3*I)*I^n)/4 where I=sqrt(-1).
a(n) = (17 - 15*cos(n*Pi/2) - 9*sin(n*Pi/2))/2. (End)
MAPLE
MATHEMATICA
PowerMod[4, Range[0, 100], 17]
PROG
(Magma) [Modexp(4, n, 17): n in [0..100]];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Apr 06 2016
STATUS
approved