OFFSET
0,2
LINKS
FORMULA
a(n) = Sum_{j=0..2} Sum_{k=0..n} C(3*n+j, 3*k)/3.
G.f.: (-1+x)/((1+x)*(8*x-1)). - R. J. Mathar, Dec 10 2014
From Elmo R. Oliveira, Aug 18 2024: (Start)
E.g.f.: exp(-x)*(7*exp(9*x) + 2)/9.
a(n) = 7*a(n-1) + 8*a(n-2) for n > 1. (End)
MATHEMATICA
LinearRecurrence[{7, 8}, {1, 6}, 20] (* Harvey P. Dale, Aug 15 2016 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Nov 29 2003
EXTENSIONS
a(20)-a(21) from Elmo R. Oliveira, Aug 18 2024
STATUS
approved