OFFSET
0,2
COMMENTS
The g.f. for the Pell numbers is 1/(1-2*x-x^2) and the g.f. M(x) for the Motzkin numbers satisfy: M(x) = 1 + x*M(x) + x^2*M(x)^2.
EXAMPLE
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Nov 18 2011
STATUS
approved