635465659921domain: NAppears in sequencesa(n) = (1 + 3^n - 2*3^(n/2))/4 if n is even, (1 + 3^n - 4*3^((n-1)/2))/4 if n odd.at n=25A107767a(n) = (A046717(n))^2 (starting with n=1).at n=12A120096a(n) = ((3^(n-1) - 1)^2)/4.at n=13A238976