1537408202domain: NAppears in sequencesNumber of magic series of order n.at n=9A052456Number of n-element subsets that can be chosen from {1,2,...,9*n} having element sum n*(9*n+1)/2.at n=9A204465Number of 9-element subsets that can be chosen from {1,2,...,18*n+9} having element sum 81*n+45.at n=4A204473