142990848

Appears in sequences

• Multiply-perfect numbers: n divides sigma(n).at n=14A007691
• 4-perfect (quadruply-perfect or sous-triple) numbers: sum of divisors of n is 4n.at n=5A027687
• Harmonic seed numbers.at n=27A035527
• Multiply perfect numbers that are also harmonic numbers but are not arithmetic numbers.at n=5A046986
• Numbers k whose average divisor is nonintegral and divides k.at n=6A046999
• Numbers m such that m = sigma(abs(k)) - 3k, where k = sigma(m) - 3m.at n=11A069146
• Multiply perfect numbers k for which the quotient sigma_3(k)/k = A001158(k)/k is nonintegral.at n=3A088844
• Multiply perfect numbers k for which the quotient sigma_5(k)/k = A001160(k)/k is nonintegral.at n=3A088845
• Numbers k that divide (sum of proper divisors of k + product of proper divisors of k).at n=14A089748
• Numbers k such that S(S(k))=k, with S(n)=sigma(n)/4: 1/4-sociable numbers of order 1 or 2.at n=11A113286
• Let S(n)=sigma(|n|)-3*n; sequence gives numbers n such that S(S(S(S(n))))=n. May be called {3,1}-Sociable number of orders 1 or 2 or 4.at n=22A114528
• A partition product of Stirling_2 type [parameter k = -6] with biggest-part statistic (triangle read by rows).at n=34A157396
• Multiply perfect numbers k such that sigma(k)/k > 2.at n=8A166069
• Numbers n such that gcd(sigma(n), n) > gcd(sigma(m), m) for all m < n.at n=27A216793
• Numbers k that divide 2*sigma(k).at n=23A246454
• Numbers n such that sigma(n+sigma(n)) = 6*sigma(n).at n=10A246913
• 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=19A282775
• Numbers k such that k divides lcm(tau(k), sigma(k)).at n=33A307740
• Numbers m having at least one divisor d such that m divides sigma(d).at n=31A323652
• Harmonic numbers m from A001599 such that m*(m-tau(m))/sigma(m) is an integer h, where k-tau(k) is the number of nondivisors of k (A049820), tau(k) is the number of divisors of k (A000005), and sigma(k) is the sum of the divisors of k (A000203).at n=16A325021