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%I #5 Mar 30 2012 17:40:41
%S 1,5,39,753,25887,1842241,247531775
%N Number of real n X n symmetric (0,1) matrices with nonzero permanent.
%F 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]
%Y Cf. A086899, A118989.
%K nonn,more
%O 1,2
%A _Giovanni Resta_, May 08 2006
%E 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