OFFSET
1,2
COMMENTS
In the first 100000 terms the only fixed point is a(1) = 1; it is unknown if more exist. The sequence is conjectured to be a permutation of the positive integers.
LINKS
Scott R. Shannon, Image for n = 1..100000. The green line is a(n) = n.
EXAMPLE
a(5) = 2 as |a(4) - a(3)| = |12 - 6| = 6, and 2 is the smallest unused number that shares a factor with 6 while the difference |2 - a(4)| = |2 - 12| = 10 is distinct from all previous differences.
CROSSREFS
KEYWORD
nonn
AUTHOR
Scott R. Shannon, Mar 07 2023
STATUS
approved