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A057411 Number of staircase polygons of perimeter 2n with 2 (staircase polygon) holes on square lattice (not allowing rotations). 1
2, 54, 737, 7330, 60362, 438284, 2908069, 18032906, 106088843, 598428100, 3261717223, 17278076588, 89351738840, 452686823796, 2253216812878, 11043624323310, 53399946187312, 255135202590382, 1206067676613670 (list; graph; refs; listen; history; text; internal format)
OFFSET
12,1
LINKS
I. Jensen, Table of n, a(n) for n = 12..75 (from link below)
I. Jensen, More terms
CROSSREFS
Sequence in context: A200195 A202739 A055024 * A157058 A305693 A357421
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Aug 30 2000
STATUS
approved

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Last modified July 22 00:58 EDT 2024. Contains 374478 sequences. (Running on oeis4.)