OFFSET
0,3
COMMENTS
FORMULA
Eigenvector: a(n) = Sum_{k=0..[n/2]} 2^k*C(n,2*k)*a(k) for n>=0, with a(0)=1. O.g.f. A(x) satisfies: A(x/(1+x))/(1+x) = A(2*x^2).
EXAMPLE
a(7) = Sum_{k=0..[7/2]} 2^k*C(7,2*k)*a(k) =
1*(1) + 42*(1) + 140*(3) + 56*(7) = 855.
PROG
(PARI) a(n)=if(n==0, 1, sum(k=0, n\2, 2^k*binomial(n, 2*k)*a(k)))
CROSSREFS
KEYWORD
eigen,nonn
AUTHOR
Paul D. Hanna, May 08 2006
STATUS
approved