A057416 - OEIS

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A057416

Number of staircase polygons of area n with 3 (staircase polygon) holes on square lattice (not allowing rotations).

1

4, 30, 184, 894, 3885, 15386, 56956, 199620, 669702, 2166462, 6798186, 20786496, 62160079, 182336358, 525931258, 1494726848, 4192885357, 11625457180, 31899800729, 86717361496, 233754981005, 625311996048

(list; graph; refs; listen; history; text; internal format)

OFFSET

18,1

LINKS

I. Jensen, Table of n, a(n) for n = 18..89 (from link below)

I. Jensen, More terms

CROSSREFS

Sequence in context: A317567 A132849 A115867 * A089154 A113450 A344399

Adjacent sequences: A057413 A057414 A057415 * A057417 A057418 A057419

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Aug 30 2000

STATUS

approved