18900

Appears in sequences

• a(n) = (5*n)!/((2*n)!*(n!)^3).at n=2A001460
• Expansion of (1+2*x+x^2)/(1-26*x+x^2).at n=3A004293
• Floor-factorial numbers: a(n) = Product_{k=1..n} floor(n/k).at n=15A010786
• a(n) = floor( n*(n-1)*(n-2)*(n-3)/26 ).at n=28A011936
• Number of lines through at least 2 points of an n X n grid of points.at n=17A018808
• Coordination sequence for lattice D*_6 (with edges defined by l_1 norm = 1).at n=7A035472
• For all n, if d is recursively applied to a(n) exactly 6 times then the fixed point of d-iteration is just reached.at n=28A036458
• Sums of 4 distinct powers of 5.at n=30A038476
• Triangular table of 2^n *(n+k)! / ((n-k)! * k! * 4^k).at n=25A043302
• Denominators of coefficients in Taylor series for log(tan(x)/x).at n=4A047686
• Number of degree-n even permutations of order exactly 4.at n=8A051695
• Triangle of number of labeled rooted trees with n nodes and k leaves, n >= 1, 1 <= k <= n.at n=24A055302
• Number of labeled rooted trees with n nodes and 4 leaves.at n=2A055305
• Irregular triangle read by rows: T(n,k) is the number of elements of alternating group A_n having order k, for n >= 1, 1 <= k <= A051593(n).at n=43A057740
• a(n) = 21*n^2.at n=30A064762
• Triangle of coefficients of Bessel polynomials {y_n(x)}'.at n=18A065931
• Triangle of coefficients of Bessel polynomials {y_n(x)}''.at n=13A065943
• Bessel polynomial {y_n}'''(0).at n=7A065949
• a(n) = (2n+1)*(2n+2)*(2n+6)*(2n+7).at n=4A069080
• Replace all prime factors p of n with n-p.at n=29A072194