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A171012 Number of ways to place two non-attacking wazirs on all free n-ominoes. 0
0, 0, 2, 14, 71, 341, 1591, 7610, 35432, 165209 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..10.

EXAMPLE

E.g. the triomino XXX admits 1 combination of 2 non-attacking wazirs.

The triomino XX admits 1 combination of 2 non-attacking wazirs.

............ X

CROSSREFS

Sequence in context: A206947 A203241 A072888 * A094583 A002058 A095933

Adjacent sequences:  A171009 A171010 A171011 * A171013 A171014 A171015

KEYWORD

nonn

AUTHOR

David Scambler, Aug 27 2010

STATUS

approved

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Last modified February 16 14:47 EST 2019. Contains 320163 sequences. (Running on oeis4.)