1112757domain: NAppears in sequencesNumber of rooted maps with n edges on the projective plane.at n=6A007137Triangle read by rows: T(n,k) = number of rooted maps with n edges on a nonorientable surface of genus k (1 <= k <= n).at n=21A267180Number of rooted maps of genus 1/2 with n edges.at n=6A361137