676792domain: NAppears in sequencesNumber of n X 3 0..3 arrays with rows and columns lexicographically nondecreasing read forwards and nonincreasing read backwards.at n=7A201976T(n,k)=Number of nXk 0..3 arrays with rows and columns lexicographically nondecreasing read forwards and nonincreasing read backwards.at n=47A201981