27926536

Appears in sequences

• Number of 3 X 3 X 3 triangular 0..n arrays with no element lying outside the (possibly reversed) range delimited by its sw and se neighbors, and no element equal to its horizontal neighbors.at n=28A214385
• a(n) = 25*binomial(n-1,6) + binomial(n-1,5).at n=29A274501