689715domain: NAppears in sequencesHalf the number of length n integer sequences with sum zero and sum of squares 2450.at n=4A157567Number of nXnXn 0..6 triangular arrays with each element x equal to the number its neighbors equal to 3,1,1,1,0,0,0 for x=0,1,2,3,4,5,6.at n=5A203209