OFFSET
1,1
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (1,0,1,-1).
FORMULA
From Chai Wah Wu, May 29 2016: (Start)
a(n) = a(n-1) + a(n-3) - a(n-4).
G.f.: x*(x^3 + x^2 + 4*x + 2)/(x^4 - x^3 - x + 1). (End)
From Wesley Ivan Hurt, Jun 10 2016: (Start)
a(n) = (24*n-3-6*cos(2*n*Pi/3)-4*sqrt(3)*sin(2*n*Pi/3))/9.
a(3k) = 8k-1, a(3k-1) = 8k-2, a(3k-2) = 8k-6. (End)
MAPLE
A047552:=n->(24*n-3-6*cos(2*n*Pi/3)-4*sqrt(3)*sin(2*n*Pi/3))/9: seq(A047552(n), n=1..100); # Wesley Ivan Hurt, Jun 10 2016
MATHEMATICA
LinearRecurrence[{1, 0, 1, -1}, {2, 6, 7, 10}, 50] (* G. C. Greubel, May 29 2016 *)
Select[Range[200], MemberQ[{2, 6, 7}, Mod[#, 8]]&] (* Harvey P. Dale, Aug 05 2018 *)
PROG
(Magma) [n : n in [0..150] | n mod 8 in [2, 6, 7]]; // Wesley Ivan Hurt, Jun 10 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved
