65418domain: NAppears in sequencesa(n) = (n/2) * Sum_{k=0..n} binomial(n,k)/gcd(n,k).at n=13A105861Expansion of g.f. A(x) satisfying Sum_{n>=0} (-1)^n * x^n * Product_{k=0..n} (x^k + A(x)) = theta_2(x^(1/2)) / x^(1/8).at n=10A369682Number of non-perfect-powers x in the range 2^n < x < 2^(n+1).at n=16A377701