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A089454
Number of n-celled polyominoes with exactly 2 holes.
4
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 41, 346, 2384, 14560, 81863, 433172, 2192752, 10726252, 51094203, 238259280, 1092053068, 4934652298, 22034767837, 97407519119, 426916828181
OFFSET
1,11
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Joseph Myers, Nov 04 2003
STATUS
approved