1360128

Appears in sequences

• a(n) = 3*(n-2)*(n-3)*(3*n^2-3*n-8)/2.at n=23A064198
• If X_1,...,X_n is a partition of a 2n-set X into 2-blocks then a(n) is equal to the number of 5-subsets of X containing none of X_i, (i=1,...n).at n=19A130811
• Number of elements of order n in simple Mathieu group M_23.at n=14A284872
• Expansion of 1/( ((1-x)*(1-2*x)*(1-3*x)*(1-4*x)*(1-5*x))^2 * (1-6*x) ).at n=5A383893