A145676 - OEIS

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A145676

Number of n X n {0,-1,1}-matrices A such that permanent( |A| ) = det A, where |A| is obtained from A by taking the absolute value of each entry.

1, 2, 49, 8419, 9162049 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,2`
	EXAMPLE	`Here are the 2 for the 1 X 1 case:` `{{{0}}, {{1}}}` `and the 49 for the 2 X 2 case:` `{{{-1, -1}, {0, -1}}, {{-1, -1}, {0, 0}}, {{-1, -1}, {1, -1}}, {{-1, -1}, {1, 0}},` `{{-1, 0}, {-1, -1}}, {{-1, 0}, {-1, 0}}, {{-1, 0}, {0, -1}}, {{-1, 0}, {0, 0}},` `{{-1, 0}, {1, -1}}, {{-1, 0}, {1, 0}}, {{-1, 1}, {-1, -1}}, {{-1, 1}, {-1, 0}},` `{{-1, 1}, {0, -1}}, {{-1, 1}, {0, 0}}, {{0, -1}, {0, -1}}, {{0, -1}, {0, 0}},` `{{0, -1}, {0, 1}}, {{0, -1}, {1, -1}}, {{0, -1}, {1, 0}}, {{0, -1}, {1, 1}},` `{{0, 0}, {-1, -1}}, {{0, 0}, {-1, 0}}, {{0, 0}, {-1, 1}}, {{0, 0}, {0, -1}},` `{{0, 0}, {0, 0}}, {{0, 0}, {0, 1}}, {{0, 0}, {1, -1}}, {{0, 0}, {1, 0}},` `{{0, 0}, {1, 1}}, {{0, 1}, {-1, -1}}, {{0, 1}, {-1, 0}}, {{0, 1}, {-1, 1}},` `{{0, 1}, {0, -1}}, {{0, 1}, {0, 0}}, {{0, 1}, {0, 1}}, {{1, -1}, {0, 0}},` `{{1, -1}, {0, 1}}, {{1, -1}, {1, 0}}, {{1, -1}, {1, 1}}, {{1, 0}, {-1, 0}},` `{{1, 0}, {-1, 1}}, {{1, 0}, {0, 0}}, {{1, 0}, {0, 1}}, {{1, 0}, {1, 0}},` `{{1, 0}, {1, 1}}, {{1, 1}, {-1, 0}}, {{1, 1}, {-1, 1}}, {{1, 1}, {0, 0}}, {{1, 1}, {0, 1}}}`
	CROSSREFS	`Cf. A145675.` `Sequence in context: A189389 A001568 A088067 * A027619 A076267 A050800` `Adjacent sequences: A145673 A145674 A145675 * A145677 A145678 A145679`
	KEYWORD	`nonn`
	AUTHOR	`E. W. Weisstein (eric(AT)weisstein.com), Mar 26, 2009`
	EXTENSIONS	`a(4) from Eric W. Weisstein (eric(AT)weisstein.com), Mar 27 2009`

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Last modified February 17 16:49 EST 2012. Contains 206058 sequences.