23668977163domain: NAppears in sequencesa(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026300.at n=12A026940Expansion of (A(x)^2+A(x^2))/2 where A(x) = A001006(x).at n=25A275207Expansion of (A(x)^2-A(x^2))/2 where A(x) = A001006(x).at n=25A275208