14182439040
domain: N
Appears in sequences
- a(n) = first n-fold perfect (or n-multiperfect) number.at n=4A007539
- Multiply-perfect numbers: n divides sigma(n).at n=19A007691
- 5-multiperfect numbers.at n=0A046060
- Multiply perfect numbers whose average divisor is an integer and divides the number itself.at n=7A046985
- Intersection of A046985 and A033950: multiply perfect, refactorable numbers with integer average divisor dividing the number.at n=5A047728
- Numbers n such that sigma(n) / n is prime.at n=11A065997
- Multiply perfect numbers k for which the quotient sigma_3(k)/k = A001158(k)/k is nonintegral.at n=4A088844
- Multiperfect numbers n which are divisible by sopfr(n) (multiperfect number: sigma(n) = k*n with k integer, sopfr: Sum of prime factors with repetition).at n=1A091443
- Multiperfect numbers sigma(n) = k*n, which are divisible by the sum of their prime factors without repetition.at n=5A114887
- Multiperfect numbers, sigma(n) = k*n, which are divisible by their sums of prime factors with and without repetition.at n=1A114888
- Multiply perfect numbers k such that sigma(k)/k > 2.at n=12A166069
- Numbers m such that k(m) = m/tau(m) - sigma(m)/m is an integer.at n=8A245778
- Refactorable multiply-perfect numbers.at n=5A245782
- Numbers n such that k(n) = (n/tau(n) + sigma(n)/n) is an integer.at n=7A245786
- Smallest x such that sigma(x)/x = 2*sigma(n)/n where sigma(n) is the sum of divisors of n.at n=23A246827
- Nonprime numbers k such that k | (sigma(k) - Sum_{j=1..m}{sigma(k) mod d_j}), where d_j is one of the m divisors of k.at n=24A282775
- a(n) = smallest m such that sigma(m) = n*m/2.at n=8A317681
- Multi-perfect numbers m from A007691 such that m*(m-tau(m))/sigma(m) is an integer h, where k-tau(k) is the number of nondivisors of k (A049820) and sigma(k) is the sum of the divisors of k (A000203).at n=15A325023
- Numbers that are multi-perfect (A007691) and simultaneously harmonic (A001599).at n=16A325025
- Refactorable numbers (A033950) that are simultaneously arithmetic (A003601) and harmonic (A001599).at n=14A331666