OFFSET
1,2
COMMENTS
See A192469.
FORMULA
Empirical G.f.: -x*(x-1)*(3*x-1)/((3*x^2+x-1)*(9*x^2-7*x+1)). [Colin Barker, Nov 12 2012]
MATHEMATICA
(See A192468.)
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Jul 01 2011
STATUS
approved