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Number of positive terms in a symmetric determinant of order n.
2

%I #3 Mar 30 2012 16:49:02

%S 1,1,1,2,8,38,193,1243,8971,77039,711719,7557974,85038784,1075040038,

%T 14252911927,208885729397,3187988600057,53129157538097,

%U 917244939572929,17127419083026706,329981266766790136,6823452191056396526,145118585159785011041

%N Number of positive terms in a symmetric determinant of order n.

%D L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 260, #12, p_n.

%Y (A002135+A059422)/2. Cf. A059424.

%K nonn

%O 0,4

%A _N. J. A. Sloane_, Jan 30 2001