Gupta, H. Enumeration of symmetric matrices. (English) Zbl 0185.03401 Duke Math. J. 35, 653-659 (1968). Page: −5 −4 −3 −2 −1 ±0 +1 +2 +3 +4 +5 Show Scanned Page Cited in 5 Documents Keywords:combinatorics PDFBibTeX XMLCite \textit{H. Gupta}, Duke Math. J. 35, 653--659 (1968; Zbl 0185.03401) Full Text: DOI Online Encyclopedia of Integer Sequences: Number of self-inverse permutations on n letters, also known as involutions; number of standard Young tableaux with n cells. Number of n X n symmetric matrices with nonnegative entries and all row sums 2. Number of n X n symmetric matrices with (0,1) entries and all row sums 2. Number of stochastic matrices of integers. Number of symmetric 0-1 (n+1) X (n+1) matrices with row sums 2 and first row starting 1,1 for n > 0, a(0)=1.