8059824domain: NAppears in sequencesa(n) = c(2n-1), where c(n+2) = Sum_{k=0..n} binomial(n,k)c(k)c(n+1-k) with c(0)=0, c(1)=3.at n=5A289070Expansion of Product_{k>=1} ((1 + x^(2*k-1)) / (1 - x^(2*k-1)))^k.at n=40A292037