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A056639
Number of polygons of length 2n with 3 (self-avoiding polygon) holes on square lattice (not allowing rotations).
2
62, 3920, 130560, 3058544, 56925214, 900355884, 12619939046, 161208191596, 1913821820768, 21416926011756, 228320059956022, 2337581305737496, 23128907576991302, 222266054948571020, 2082868947950189248
OFFSET
16,1
LINKS
I. Jensen, Table of n, a(n) for n = 16..45 (from link below)
I. Jensen, More terms
CROSSREFS
Cf. A002931.
Sequence in context: A206895 A207285 A042861 * A289297 A123806 A233340
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Aug 30 2000
STATUS
approved