335920

Appears in sequences

• a(n) = number of (s(0), s(1), ..., s(n)) such that s(i) is a nonnegative integer and |s(i) - s(i-1)| = 1 for i = 1,2,...,n and s(0) = 3. Also a(n) = Sum{T(n,k), k = 0,1,...,[ (n+3)/2 ]}, where T is defined in A026022.at n=19A026023
• a(n) = 2 * C(2*n,n-1).at n=10A162551
• Expansion of 1/((1-x)^2*(1-x^2)^3*(1-x^3)^2*(1-x^4)).at n=38A210068
• G.f. for Ehrhart quasi-polynomials for hyperplane arrangements of type E_7.at n=56A210633
• Second column of the extended Catalan triangle A189231.at n=20A238452
• Convolution of the generalized Catalan numbers A057977 with themselves.at n=19A239453
• Number of preferential arrangements of n labeled elements such that the minimal number of elements per rank equals 9.at n=11A245862
• a(n) is the number of ballot sequences of length n tied or won by at most 3 votes.at n=19A337500
• Denominator of Sum_{1<=j<=k<=n, gcd(j,k)=1} 1/(j*k).at n=21A365228