180936

Appears in sequences

• Number of ways of placing non-attacking knights on an n X n chessboard symmetric about main diagonal.at n=7A130613
• Central terms of triangle A194949 = sums of squares of terms in rows of triangle A194949.at n=6A194951
• Triangle T(n,k) read by rows: coefficients of polynomials P_n(t) defined in Formula section.at n=29A291843
• E.g.f.: exp(-x^3 * exp(x)).at n=9A293017
• Irregular triangle read by rows: T(n,k) is the number of essential graphs with n nodes and k (directed or undirected) edges (n >= 1, 0 <= k <= n*(n-1)/2).at n=35A368569