173600

Appears in sequences

• Harmonic or Ore numbers: numbers k such that the harmonic mean of the divisors of k is an integer.at n=21A001599
• Numbers whose divisors' harmonic and arithmetic means are both integers.at n=18A007340
• Harmonic seed numbers.at n=12A035527
• Numbers k such that the harmonic mean of the divisors of k is the square of a rational number.at n=24A074266
• Harmonic numbers (A001599) which are not perfect (A000396).at n=17A090945
• a(n) = smallest number m such that m*tau(m)/sigma(m) = n, or 0 if no such m exists.at n=24A091911
• Harmonic numbers that are not multiply-perfect.at n=13A140798
• Corresponding values of arithmetic means of divisors of numbers from A007340.at n=39A157848
• Coefficient of x in the reduction by x^2->x+3 of the polynomial p(n,x)=1+x^n+x^(2n).at n=7A192469
• Number of ON cells in 3-D cellular automaton described in Comments, after n generations.at n=55A246031
• Number of ON cells in 3-D cellular automaton described in Comments, after n generations.at n=59A246031
• E.g.f.: Limit_{N->oo} [ Sum_{n>=0} (N + n*y)^(2*n) * (x/N)^n/n! ]^(1/N).at n=39A266488
• Harmonic numbers m from A001599 such that m*(m-tau(m))/sigma(m) is not an integer, where k-tau(k) = the number of nondivisors of k (A049820), tau(k) = the number of divisors of k (A000005) and sigma(k) = the sum of the divisors of k (A000203).at n=13A325022
• Numbers k such that squarefree part of sigma(k) is equal to squarefree part of 2*k.at n=25A331752
• Harmonic numbers k such that k*p is not a harmonic number for all the primes p that do not divide k.at n=8A335369
• Numbers k such that the continued fraction of the harmonic mean of the divisors of k contains a single distinct element.at n=30A349476