20056584

Appears in sequences

• Number of reversible strings with n-1 black beads and n-1 white beads. String is not palindromic.at n=14A032095
• a(n) = Sum_{k=0..n} binomial(2*n,2*k)^2.at n=7A098772
• Number of n-element subsets of [2n] having an even sum.at n=14A119358
• Expansion of g(x) - x*g(x^2), where g(x) is the g.f. of A001405.at n=27A129383