OFFSET
1,2
COMMENTS
A057660(n) is a multiplicative function bounded above by n*(n-1)+1, which is reached whenever n is 1 or prime. These numbers are the n such that the ratio between A057660(n) and the upper bound reaches a record low.
Motivated by Daniel Forgues's conjecture that this sequence consists of 4 and A051451.
A subsequence of A025487.
LINKS
Charlie Neder, Table of n, a(n) for n = 1..215
EXAMPLE
A057660(60060)/(60060*60059+1) = 1211716737/3607143541 ~ 0.3359214, and every number less than 60060 has a ratio > 0.34, so 60060 is in this sequence.
CROSSREFS
KEYWORD
nonn
AUTHOR
Charlie Neder, May 29 2019
STATUS
approved