21672

Appears in sequences

• Expansion of 1/((1-x)(1-2x)(1-4x)(1-5x)).at n=5A021074
• a(n) = Sum_{k=0..n-3} T(n,k) * T(n,k+3), with T given by A026374.at n=5A026949
• Multiplicity of highest weight (or singular) vectors associated with character chi_119 of Monster module.at n=43A034507
• Base 7 digits are, in order, the first n terms of the periodic sequence with initial period 1,2,0.at n=5A037508
• a(n) = 12*n*(n-1).at n=43A064200
• Number of solutions (x,y,z,u,v,w) to x+y+z = u+v+w, 0<=x,y,z,u,v,w<=n-1, x>=y>=z, u>=v>=w.at n=15A071009
• a(n) = n*phi(n*phi(n)).at n=42A078774
• Triangle, read by rows, of trinomial coefficients arranged so that there are n+1 terms in row n by setting T(n,k) equal to the coefficient of z^k in (1 + 3*z + z^2)^(n-[k/2]), for n>=k>=0, where [k/2] is the integer floor of k/2.at n=60A099512
• Riordan array (1/sqrt(1-6x+5x^2),(1-3x-sqrt(1-6x+5x^2))/(2x)).at n=39A110165
• Triangle read by rows: T(n,k) is the number of hex trees with n edges and k pairs of adjacent vertices of outdegree 2.at n=30A126188
• Triangle read by rows, X^n * [1,0,0,0,...]; where X = a tridiagonal matrix with (1,2,3,...) in the main diagonal and (1,1,1,...) in the sub and subsubdiagonals.at n=53A140735
• a(n) = 729*n - 198.at n=29A156772
• Number of (w,x,y,z) with all terms in {1,...,n} and median<=mean.at n=14A212134
• The hyper-Wiener index of the linear phenylene with n hexagons.at n=5A224455
• Number of conjugacy classes of the symmetric group S_n when conjugating only by even permutations.at n=36A242101
• Number of cds-sortable permutations in S_n. That is, number of permutations for which application of some sequence of context directed swaps ("cds" operations) terminates in the identity.at n=7A249165
• Positive even numbers which are neither of the form p + 2^m + 1 nor of the form p + 2^m - 1 with p prime.at n=34A270446
• Triangle read by rows, T(n,k) are covariances of inverse power traces of complex Wishart matrices with parameter c=2, for n>=1 and 1<=k<=n.at n=15A272865
• Number of (undirected) paths in the n-cocktail party graph.at n=3A286038
• Numerator of sigma_3(n)/sigma_2(n).at n=41A298754