2091375domain: NAppears in sequencesOdd numbers taking exactly 21 steps to reach 15 in A086793.at n=13A119398Sixth column (k=5) of triangle A134832 (circular succession numbers).at n=8A135803Irregular triangle M_2(n,k) read by rows: number of maximum k-matchings in rooted plane trees of size n, 1<=k<=n/2, 2<=n.at n=44A219731