60400domain: NAppears in sequencesn*(n-1)*(n^2-n+4)/6.at n=25A103290Number of 6-step S, NW and NE-moving king's tours on an n X n board summed over all starting positions.at n=20A187380Numbers k such that the sums (with multiplicity) of prime factors of k and k+1 are both squares.at n=42A359445