OFFSET
1,1
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*(1+x)*(x^2+x+2) / ((1+x+x^2)*(x-1)^2). - R. J. Mathar, Oct 08 2011
From Wesley Ivan Hurt, Jun 10 2016: (Start)
a(n) = a(n-1) + a(n-3) - a(n-4) for n>4.
a(n) = (24*n-6-3*cos(2*n*Pi/3)-sqrt(3)*sin(2*n*Pi/3))/9.
a(3k) = 8k-1, a(3k-1) = 8k-3, a(3k-2) = 8k-6. (End)
a(n) = A047408(n) + 1. - Lorenzo Sauras Altuzarra, Jan 31 2023
MAPLE
A047480:=n->(24*n-6-3*cos(2*n*Pi/3)-sqrt(3)*sin(2*n*Pi/3))/9: seq(A047480(n), n=1..100); # Wesley Ivan Hurt, Jun 10 2016
MATHEMATICA
Select[Range[0, 150], MemberQ[{2, 5, 7}, Mod[#, 8]] &] (* Wesley Ivan Hurt, Jun 10 2016 *)
Flatten[Table[8 n + {2, 5, 7}, {n, 0, 150}]] (* Vincenzo Librandi, Jun 12 2016 *)
LinearRecurrence[{1, 0, 1, -1}, {2, 5, 7, 10}, 100] (* Harvey P. Dale, Jun 18 2018 *)
PROG
(Magma) [n : n in [0..150] | n mod 8 in [2, 5, 7]]; // Wesley Ivan Hurt, Jun 10 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved