OFFSET
1,2
LINKS
Vincenzo Librandi, 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 28 2016: (Start)
a(n) = a(n-1) + a(n-3) - a(n-4) for n>4.
G.f.: x^2*(x^2 + 5*x + 2)/(x^4 - x^3 - x + 1). (End)
a(n) = (24*n + 2*sqrt(3)*sin(2*Pi*n/3) + 12*cos(2*Pi*n/3) - 21)/9. - Ilya Gutkovskiy, May 29 2016
a(3k) = 8k-1, a(3k-1) = 8k-6, a(3k-2) = 8k-8. - Wesley Ivan Hurt, Jun 10 2016
E.g.f.: 1 + (3*exp(x)*(8*x - 7) + 2*exp(-x/2)*(6*cos(sqrt(3)*x/2) + sqrt(3)*sin(sqrt(3)*x/2)))/9. - Stefano Spezia, Dec 31 2022
MAPLE
A047525:=n->(24*n+2*sqrt(3)*sin(2*Pi*n/3)+12*cos(2*Pi*n/3)-21)/9: seq(A047525(n), n=1..100); # Wesley Ivan Hurt, Jun 10 2016
MATHEMATICA
Flatten[# + {0, 2, 7} &/@(8 Range[0, 30])] (* Vincenzo Librandi, May 29 2016 *)
PROG
(Magma) [n: n in [0..200] | n mod 8 in [0, 2, 7]]; // Vincenzo Librandi, May 29 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved