245156

Appears in sequences

• Number of nonempty subsets of {1,2,...,n} in which exactly 1/2 of the elements are <= n/3.at n=22A047193
• Number of nonempty subsets of {1,2,...,n} in which exactly 1/2 of the elements are <= (n-1)/3.at n=22A048005
• Number of nonempty subsets of {1,2,...,n} in which exactly 1/2 of the elements are <= (n-2)/3.at n=22A048016
• a(n) = C(n,7)-1.at n=16A124090
• Number of active (ON, black) cells at stage 2^n-1 of the two-dimensional cellular automaton defined by "Rule 213", based on the 5-celled von Neumann neighborhood.at n=8A270902
• Coefficient of x^n in the expansion of ( (1+x)^2 * (1+x^3) )^n.at n=9A370196