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

Adjacent sequences:  A056636 A056637 A056638 * A056640 A056641 A056642

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Aug 30 2000

STATUS

approved

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Last modified November 20 02:34 EST 2019. Contains 329323 sequences. (Running on oeis4.)