A057410 Number of staircase polygons of perimeter 2n with one (staircase polygon) hole on square lattice (not allowing rotations).

1, 12, 94, 604, 3463, 18440, 93274, 454412, 2151673, 9964500, 45335002, 203303760, 900901387, 3952468348, 17194102478, 74257185512, 318693463933, 1360298775524, 5778468266446, 24442845038580

Offset: 8

Author

N. J. A. Sloane, Aug 30 2000, corrected Aug 29 2006

Keywords

• nonn

Links

• I. Jensen, Table of n, a(n) for n = 8..103 (from link below)
• I. Jensen, More terms