2142720

Appears in sequences

• a(n) is the sum of the divisors of Fibonacci(n) (A000045).at n=29A063477
• Numbers n for which sigma(n)/n=k+2/3 with integer k.at n=7A160321
• Numbers n such that gcd(sigma(n), n) > gcd(sigma(m), m) for all m < n.at n=18A216793
• Numbers k that divide 3*sigma(k).at n=24A245774
• Numbers k such that A017666(k) = denominator(sigma(k)/k) = 3.at n=14A245775
• Integers k such that numerator and denominator of sigma(k)/k are both prime.at n=25A247086
• Numbers m such that the sum of the first k divisors of m, for some k, is equal to the sum of its other divisors.at n=9A334410