27131

Appears in sequences

• Number of nonempty subsets of {1,2,...,n} in which exactly 1/2 of the elements are <= n/3.at n=18A047193
• Number of nonempty subsets of {1,2,...,n} in which exactly 1/2 of the elements are <= (n-1)/3.at n=18A048005
• Number of nonempty subsets of {1,2,...,n} in which exactly 1/2 of the elements are <= (n+1)/3.at n=18A048038
• a(n) = binomial(n,6)-1.at n=13A124089
• Number of 0..n arrays x(0..4) of 5 elements without any interior element greater than both neighbors or less than both neighbors.at n=11A200873
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 35", based on the 5-celled von Neumann neighborhood.at n=34A269816
• Number of n-bead ternary necklaces (no turning over allowed) that avoid the subsequence 110.at n=12A274018
• a(n) = (Sum_{k=0..n-1}(840*k+197)(-1)^k*2430^(n-1-k)*T_k(8,1)*T_k(5,-5)^2)/(n*5^(n-1)), where T_k(b,c) denotes the coefficient of x^k in the expansion of (x^2+b*x+c)^k.at n=1A329107