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 A118991 Number of real n X n symmetric (0,1) matrices with nonzero permanent. 2
 1, 5, 39, 753, 25887, 1842241, 247531775 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Table of n, a(n) for n=1..7. FORMULA a(n) = 2^(n(n+1)/2) - A118989(n) = 2^A000217(n) - A118989(n) = A006125(n+1) - A118989(n). [From Max Alekseyev, Apr 22 2010] CROSSREFS Cf. A086899, A118989. Sequence in context: A221412 A193118 A227636 * A253920 A156378 A220061 Adjacent sequences: A118988 A118989 A118990 * A118992 A118993 A118994 KEYWORD nonn,more AUTHOR Giovanni Resta, May 08 2006 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 STATUS approved

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Last modified May 19 20:35 EDT 2024. Contains 372703 sequences. (Running on oeis4.)