550560domain: NAppears in sequencesNumbers k such that k and k^2 use only the digits 0, 1, 3, 5 and 6.at n=49A136843G.f. A(x) satisfies: A(x) = (1-x)^3*A(x)^2 - x^2*A'(x).at n=10A143739a(1)=2; for n > 1, a(n) = 2^(n-2) + (1/(2n-2)) * Sum_{ d divides n-1 } phi(2d)*2^((n-1)/d).at n=20A216957