6487445domain: NAppears in sequencesa(n) = Sum_{k=0..n} (k!)^2 * Stirling_2(n,k)^2.at n=6A048144Number of permutations of length n within distance 5.at n=12A154654a(n) = largest term in row n of array in A272644.at n=10A272645Triangle read by rows: chromatic invariant T(n,m) of the complete bipartite graph K_{m,n}.at n=27A291774