216720

Appears in sequences

• a(n) = (n+1)!/2 + (n-1)(n-1)!.at n=7A000780
• Number of 2n-step self-avoiding closed paths on the 6-dimensional cubic lattice.at n=3A010570
• E.g.f. (1-2x^2)/(1-x-2x^2).at n=7A052653
• A Jacobsthal number related number triangle.at n=29A110321
• Number of pairs of consecutive non-fixed points in all permutations of {1,2,...,n}.at n=6A162968
• a(n) is the least positive number whose divisors have all possible residues mod n.at n=42A280171
• a(n) = n! * Sum_{k=1..n} 1/floor(n/k).at n=7A345683
• Triangle read by rows, T(n, k) = binomial(n, k) * k! * Stirling2(n-k, k), for n >= 0 and 0 <= k <= n//2, where '//' denotes integer division.at n=33A362369
• Triangle of numbers read by rows, T(n, k) = (n*(n-1)*(n-2))*Stirling2(k, 3), for n >= 1 and 1 <= k <= n.at n=51A362791
• Table read by rows: T(n, k) = A124320(n + 1, k) * A048993(n, k).at n=31A368584
• The smallest number whose divisor set mod p has p elements with p = prime(n).at n=13A378272