OFFSET
1,3
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..3000
Index entries for linear recurrences with constant coefficients, signature (1,0,1,-1).
FORMULA
G.f.: x^2*(1+5*x+2*x^2)/((1+x+x^2)*(x-1)^2). - R. J. Mathar, Dec 05 2011
From Wesley Ivan Hurt, Jun 09 2016: (Start)
a(n) = a(n-1) + a(n-3) - a(n-4) for n>4.
a(n) = 8*n/3-3+cos(2*n*Pi/3)+5*sin(2*n*Pi/3)/(3*sqrt(3)).
a(3k) = 8k-2, a(3k-1) = 8k-7, a(3k-2) = 8k-8. (End)
MAPLE
A047394:=n->8*n/3-3+cos(2*n*Pi/3)+5*sin(2*n*Pi/3)/(3*sqrt(3)): seq(A047394(n), n=1..100); # Wesley Ivan Hurt, Jun 09 2016
MATHEMATICA
Select[Range[0, 150], MemberQ[{0, 1, 6}, Mod[#, 8]] &] (* Wesley Ivan Hurt, Jun 09 2016 *)
PROG
(Magma) [n : n in [0..150] | n mod 8 in [0, 1, 6]]; // Wesley Ivan Hurt, Jun 09 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved