18780

Appears in sequences

• Sums of 4 distinct powers of 5.at n=27A038476
• Number of nonempty subsets of {1,2,...,n} in which exactly 3/4 of the elements are <= n/3.at n=28A047197
• Number of nonempty subsets of {1,2,...,n} in which exactly 3/4 of the elements are <= (n-1)/3.at n=28A048009
• Number of nonempty subsets of {1,2,...,n} in which exactly 3/4 of the elements are <= (n-2)/3.at n=28A048020
• Triangle read by rows: T(n,k) is the number of paths in the right half-plane, from (0,0) to (n,0), consisting of steps U=(1,1), D=(1,-1), h=(1,0) and H=(2,0), having k U steps (0 <= k <= floor(n/2)).at n=38A132886
• Triangle read by rows: T(n,k) is the number of weighted lattice paths in L_n having k (1,1)-steps. L_n is the set of lattice paths of weight n that start at (0,0) and end on the horizontal axis and whose steps are of the following four kinds: a (1,0)-step with weight 1; a (1,0)-step with weight 2; a (1,1)-step with weight 2; a (1,-1)-step with weight 1. The weight of a path is the sum of the weights of its steps.at n=37A182880
• Triangle read by rows: coefficients of polynomials Q_n(x) arising in study of Riemann zeta function.at n=18A217940
• G.f.: exp( Sum_{n>=1} (sigma(2*n) - sigma(n))*Lucas(n)*x^n/n ), where Lucas(n) = A000204(n) and sigma(n) = A000203(n) is the sum of divisors of n.at n=10A225524
• Expansion of g.f. 1/ (1-x^1*(1-x^(m+1))/ (1-x^2*(1-x^(m+2))/ (1- ... ))) for m=9.at n=20A228645
• Number of nX4 0..2 arrays with no element equal to zero plus the sum of elements to its left or zero plus the sum of elements above it or zero plus the sum of the elements diagonally to its northwest, modulo 3.at n=14A240035
• Number of partitions of n such that the m(number of distinct parts) is a part, where m = multiplicity.at n=43A240307
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 259", based on the 5-celled von Neumann neighborhood.at n=29A271056
• a(n) = usigma(A276086(n)), where usigma (A034448) is multiplicative with a(p^e) = (p^e)+1, and A276086 gives the prime product form of primorial base expansion of n.at n=29A348996
• Irregular triangle read by rows: T(n, k) is the number of n-step closed walks on the hexagonal lattice having algebraic area k.at n=59A353091