515770

Appears in sequences

• Square root of number of nX4 arrays of occupancy after each element moves to some horizontal or vertical neighbor, with every occupancy equal to zero or two.at n=14A221313
• G.f. satisfies A(x) = Sum_{n>=1} 2^(n-1) * A(x^(2*n))/A(x^n), with A(0) = 0 and A'(0) = 1.at n=19A378262