277560360

Appears in sequences

• Smallest x such that sigma(x) = n*phi(x), or -1 if no such x exists.at n=25A055234
• Denominator of sum of first n terms of the series 1/3 + 1/8 + 1/24 ... in which the denominators are one less than a perfect square that cannot otherwise be written as a power (cf. A062757, A037450).at n=27A062834
• a(n) = Min{x : sigma(x) = n*phi(x), x is not a prime}, the least nonprime solutions to sigma(x) = n*phi(x); special balanced numbers.at n=25A088830
• Balanced numbers (A020492) k with a record value of sigma(k)/phi(k).at n=14A335287