OFFSET
0,2
COMMENTS
In general, Sum_{k=0..n} C(n+2k,3k)*r^k has g.f. (1-r*x)^2/(1-(3r+1)*x+3r^2*x^2-r^3*x^3). - Paul Barry, Aug 23 2007
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..200
Index entries for linear recurrences with constant coefficients, signature (7, -12, 8).
FORMULA
G.f.: (1-4x+4x^2)/(1-7x+12x^2-8x^3). - Ralf Stephan, Dec 02 2004
a(n) = Sum_{k=0..n} C(n+2k,3k)*2^(n-k). - Paul Barry, Aug 23 2007
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Mar 25 2004
STATUS
approved