522854domain: NAppears in sequencesNumber of different ways to select 4 disjoint subsets from {1..n} with equal element sum.at n=17A164949Number of n X 3 binary arrays with rows lexicographically nondecreasing and columns lexicographically nondecreasing and row sums nondecreasing and column sums nonincreasing.at n=30A266930