0,2

G.f.: 1/sqrt(1-8x^2)+(1-sqrt(1-8x^2))/(2x); a(n)=sum{k=0..floor(n/2), 2^(n-k)*C(k)C(k+1, n-k)}.

Cf. A025225, A059304.

Sequence in context: A013140 A155720 A155725 this_sequence A129826 A009296 A068554

Adjacent sequences: A103970 A103971 A103972 this_sequence A103974 A103975 A103976

easy,nonn

Paul Barry (pbarry(AT)wit.ie), Feb 23 2005