A057415 Number of staircase polygons of area n with 2 (staircase polygon) holes on square lattice (not allowing rotations).

2, 10, 53, 220, 845, 2975, 9936, 31640, 97283, 290173, 844729, 2408213, 6746197, 18613290, 50688554, 136464665, 363724034, 960862781, 2518380075, 6554072749, 16949040877, 43580221577, 111475092069, 283799832989

Offset

13,1

Links

I. Jensen, Table of n, a(n) for n = 13..86 (from link below)

I. Jensen, More terms

Crossrefs

Sequence in context: A080117 A080118 A086546 * A373907 A037724 A037619

Adjacent sequences: A057412 A057413 A057414 * A057416 A057417 A057418

Keyword

nonn

Author

N. J. A. Sloane, Aug 30 2000

Status

approved