906373domain: NAppears in sequencesNumbers n such that n=d_1!!^2+d_2!!^2+...+d_k!!^2 where d_1d_2...d_k is the decimal expansion of n.at n=4A139409Norm of coefficients in the expansion of 1 / (1 - 3*x + 2*I*x^2), where I^2=-1.at n=6A218136