638045608200domain: NAppears in sequencesMultinomial coefficient n!/([n/3]![(n+1)/3]![(n+2)/3]!).at n=28A022916Number of n X 2 0..2 arrays with values 0..2 introduced in row major order, the number of instances of each value within one of each other, and no element equal to any horizontal or vertical neighbor.at n=27A199127