614429672

Appears in sequences

• a(n) = 2^(n-1) + ((1 + (-1)^n)/4)*binomial(n, n/2).at n=30A027306
• a(n) = Sum_{i=0..n} binomial(2*n, i).at n=15A032443
• Expansion of ((1 + x - 2x^2) + (1+x)*sqrt(1-4x^2))/(2(1-4x^2)).at n=31A116406