80474domain: NAppears in sequencesNumbers k such that k and k^2 use only the digits 0, 4, 6, 7 and 8.at n=17A136954Expansion of Sum_{0<i<j<k<l} q^(2*(i+j+k+l)-4)/( (1-q^(2*i-1))*(1-q^(2*j-1))*(1-q^(2*k-1))*(1-q^(2*l-1)) )^2.at n=36A365666