OFFSET
0,2
COMMENTS
Self-convolution of A118398, which is also an eigenvector of the triangle defined by T(n,k) = 2^k*C(n,2*k).
FORMULA
Eigenvector: a(n) = Sum_{k=0..[n/2]} 2^k*C(n+1,2*k+1)*a(k) for n>=0, with a(0)=1. O.g.f. A(x) satisfies: A(x/(1+x))/(1+x)^2 = A(2*x^2).
EXAMPLE
a(7) = Sum_{k=0..[7/2]} A105070(7,k)*a(k) =
8*(1) + 112*(2) + 224*(7) + 64*(20) = 3080.
PROG
(PARI) a(n)=if(n==0, 1, sum(k=0, n\2, 2^k*binomial(n+1, 2*k+1)*a(k)))
CROSSREFS
KEYWORD
eigen,nonn
AUTHOR
Paul D. Hanna, May 08 2006
STATUS
approved