104720

Appears in sequences

• One half of triple factorial numbers.at n=5A034000
• a(n) = 2*binomial(n,4).at n=35A034827
• a(n) = (n+1)*a(n-3), a(0)=a(1)=a(2)=1 for n>1.at n=16A081406
• Number of ways to change three non-identical letters in the word aabbccdd..., where there are n types of letters.at n=33A102860
• An invertible triangle of ratios of triple factorials.at n=22A112333
• Numbers k not divisible by 6 such that sigma(k) > 3*k.at n=4A126104
• A vector sequence with set row sum function: row(n)=-Product[3*k - 1, {k, 0, n}] and linear build up and decline function: f(n,m)=Floor[(m/n)*row(n)].at n=24A152972
• Triple factorials n!!!: a(n) = n*a(n-3).at n=17A161474
• Number of partitions of n+9 with largest inscribed rectangle having area <= n.at n=37A218630
• Number of non-equivalent ways to tile an n X n X n triangular area with two 2 X 2 X 2 triangular tiles and an appropriate number (= n^2-8) of 1 X 1 X 1 tiles.at n=32A286444
• a(n) = n! * [x^n] 1/(1 - 3*x)^(n/3).at n=5A303486
• Square array A(n,k), n >= 0, k >= 1, read by antidiagonals: A(n,k) = n! * [x^n] 1/(1 - k*x)^(n/k).at n=33A303489
• Numbers k such that A122111(k) [conjugated prime factorization of k] is one of Ore's Harmonic numbers (in A001599).at n=18A336317
• Irregular triangle read by rows: T(n,k) is the number of endofunctions on [n] whose second-largest component has size exactly k; n >= 0, 0 <= k <= floor(n/2).at n=19A350078