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A057415 Number of staircase polygons of area n with 2 (staircase polygon) holes on square lattice (not allowing rotations). 1
2, 10, 53, 220, 845, 2975, 9936, 31640, 97283, 290173, 844729, 2408213, 6746197, 18613290, 50688554, 136464665, 363724034, 960862781, 2518380075, 6554072749, 16949040877, 43580221577, 111475092069, 283799832989 (list; graph; refs; listen; history; text; internal format)
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 * A037724 A037619 A221610

Adjacent sequences:  A057412 A057413 A057414 * A057416 A057417 A057418

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Aug 30 2000

STATUS

approved

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Last modified October 18 11:56 EDT 2018. Contains 316321 sequences. (Running on oeis4.)