OFFSET
1,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (1,0,1,-1).
FORMULA
G.f.: x^2*(2+x+4*x^2) / ((1+x+x^2)*(x-1)^2). - R. J. Mathar, Dec 04 2011
From Wesley Ivan Hurt, Jun 08 2016: (Start)
a(n) = a(n-1) + a(n-3) - a(n-4) for n>4.
a(n) = (21*n-27-9*cos(2*n*Pi/3)+sqrt(3)*sin(2*n*Pi/3))/9.
a(3k) = 7k-4, a(3k-1) = 7k-5, a(3k-2) = 7k-7. (End)
MAPLE
A047359:=n->(21*n-27-9*cos(2*n*Pi/3)+sqrt(3)*sin(2*n*Pi/3))/9: seq(A047359(n), n=1..100); # Wesley Ivan Hurt, Jun 08 2016
MATHEMATICA
Select[Range[0, 150], MemberQ[{0, 2, 3}, Mod[#, 7]]&] (* Harvey P. Dale, Dec 06 2012 *)
PROG
(Magma) [n : n in [0..150] | n mod 7 in [0, 2, 3]]; // Wesley Ivan Hurt, Jun 08 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved