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A118989
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Number of symmetric n X n (0,1)-matrices over the reals with zero permanent.
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2
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OFFSET
| 1,2
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FORMULA
| a(n) = 2^(n*(n+1)/2) - A118991(n) = 2^A000217(n) - A118991(n) = A006125(n+1) - A118991(n). [From Max Alekseyev (maxale(AT)gmail.com), Apr 22 2010]
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CROSSREFS
| Cf. A086906, A088672, A118991.
Sequence in context: A009042 A080896 A126746 * A123989 A001907 A181085
Adjacent sequences: A118986 A118987 A118988 * A118990 A118991 A118992
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KEYWORD
| nonn,more
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AUTHOR
| Giovanni Resta (g.resta(AT)iit.cnr.it), May 08 2006
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EXTENSIONS
| Max Alekseyev's formula corrected (the term 2^(n^2), counting the total number of binary matrices, has been substituted for 2*2^2*...*2^n = 2^(n(n+1)/2), the total number of binary symmetric matrices) by Herman Jamke (hermanjamke(AT)fastmail.fm), Sep 26 2010
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