199564domain: NAppears in sequencesa(n) = n for n <= 2; for n > 2, a(n) = 2a(n-1) - a(n - floor(1/2 + sqrt(2(n-1)))).at n=22A096824Number of nXnXn 0..6 triangular arrays with each element x equal to the number its neighbors equal to 4,1,2,1,1,0,2 for x=0,1,2,3,4,5,6.at n=5A198037