4195328domain: NAppears in sequencesa(n) = (2^n + 2^[ n/2 ] )/2.at n=21A001445G.f. satisfies: A(x) = 1 + x*A(x)/A(-x) + x^2*A(x)^2/A(-x)^2.at n=16A143560a(n) = 2^(2n) + 2^(n-1).at n=10A164051a(n) = 2^(n-2)*(2^(n+4)-(-1)^n+5).at n=10A240525G.f. A(x,y) satisfies: A(x,y) = x*y + A(x,x*y)^2, with A(0,y) = 1.at n=86A275670