-3470

Appears in sequences

• G.f. (1-x) * Sum_{n>=0} x^n * (1 + x^n)^n / (1 + x^(n+1))^(n+1).at n=51A354247
• a(n) = [(x*y)^n] Product_{k>=1} (1 - x^k - y^k)^k.at n=14A381011