208896

Appears in sequences

• Number of pair-exchange / set-rotate sequences achieving the minimum length of A048200(n).at n=12A061545
• Numbers k such that usigma(phi(k)) is a prime.at n=35A065875
• 14-almost primes (generalization of semiprimes).at n=28A069275
• Numbers k such that phi(k) is a perfect 8th power.at n=24A078168
• Expansion of (1 - 2x + 2x^2 - x^3)/(1 - 2x)^2.at n=15A084860
• Expansion of (1-4*x)/(1-4*x-4*x^2).at n=9A094013
• a(1) = 1, a(2) = (2*1)/1 = 2. a(n+1) = (n+1)*a(n) divided by the largest prime divisor of a(n).at n=16A100773
• Expansion of 4*x/(1 - 4*x - 4*x^2).at n=8A106568
• Product of n^2 and n-th tetrahedral number: a(n) = n^3*(n+1)*(n+2)/6.at n=16A119771
• A007318 * A000125.at n=12A134396
• Triangle read by rows: T(n,k) is the number of permutations p of {1,2,...,n} for which the number of j < ceiling(n/2) such that p(j) + p(n+1-j) = n+1 is equal to k (n>=1; 0<=k <=ceiling(n/2)).at n=28A155517
• Number of permutations p of {1,2,...,n} such that p(j) + p(n+1-j) != n+1 for all j.at n=9A155518
• Sequence a(n) gives the number of ways to seat 2n people around a circular table so that person i does not sit across from person n+i for any 1 <= i <= n.at n=4A167406
• Binomial transform of A005563.at n=12A176027
• Numbers n such that sigma(n) - 1 and sigma(phi(n)) are both primes.at n=26A270416
• Decimal representation of the x-axis, from the left edge to the origin, of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 126", based on the 5-celled von Neumann neighborhood.at n=17A274059
• Numbers h such that 2^phi(h) == phi(h) (mod h).at n=35A292544
• Heinz numbers of integer partitions whose length is 2/3 their sum.at n=31A348384
• Heinz numbers of integer partitions whose product equals their length.at n=22A353699