881280

Appears in sequences

• a(n) = sigma(sigma(...(sigma(n))...)) / n, where sigma (A000203) is iterated until a multiple of n is reached.at n=24A019295
• Value of phi in arithmetic progression of at least 5 terms having the same value of phi in A050515.at n=22A050517
• Value of phi in arithmetic progression of at least 5 terms having the same value of phi in A050515.at n=25A050517
• The following triangle contains n smallest numbers with the prime signature of n!. Sequence contains the triangle by rows.at n=40A111467
• a(n) is the sum of the divisors of the smallest number k such that the symmetric representation of sigma(k) has n parts.at n=15A266094
• a(n) = sigma^m(N)/N for N = A019276(n) (megaperfect numbers), where m(N) = min {m: N | sigma^m(N)} reaches record values; sigma^m is m-fold iteration of A000203.at n=7A331035
• Numbers m with a divisor d such that tau(d) * sigma(d) = m.at n=29A331668
• Numbers k such that squarefree part of sigma(k) is equal to squarefree part of 2*k.at n=41A331752