OFFSET
1,1
LINKS
Index entries for linear recurrences with constant coefficients, signature (1,0,1,-1).
FORMULA
G.f.: x*(4+x+2*x^2+x^3)/((1+x+x^2)*(x-1)^2). - R. J. Mathar, Nov 06 2015
From Wesley Ivan Hurt, Jun 09 2016: (Start)
a(n) = a(n-1) + a(n-3) - a(n-4) for n>4.
a(n) = (24*n-9*cos(2*n*Pi/3)+5*sqrt(3)*sin(2*n*Pi/3))/9.
a(3k) = 8k-1, a(3k-1) = 8k-3, a(3k-2) = 8k-4. (End)
MAPLE
A047491:=n->(24*n-9*cos(2*n*Pi/3)+5*sqrt(3)*sin(2*n*Pi/3))/9: seq(A047491(n), n=1..100); # Wesley Ivan Hurt, Jun 09 2016
MATHEMATICA
Select[Range[0, 150], MemberQ[{4, 5, 7}, Mod[#, 8]] &] (* Wesley Ivan Hurt, Jun 09 2016 *)
LinearRecurrence[{1, 0, 1, -1}, {4, 5, 7, 12}, 60] (* Harvey P. Dale, Feb 06 2019 *)
PROG
(Magma) [n : n in [0..150] | n mod 8 in [4, 5, 7]]; // Wesley Ivan Hurt, Jun 09 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved