81826

Appears in sequences

• Number of self-avoiding polygons of length 2n on square lattice (not allowing rotations).at n=9A002931
• Number of permutations that are 2 "block reversals" away from 12...n.at n=24A007972
• Number of n X 3 arrays of the minimum value of corresponding elements and their horizontal or vertical neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..1 n X 3 array.at n=35A219286