OFFSET
1,2
COMMENTS
Six loops are possible. There are three loops of one.
21.0% of the numbers end up as zero.
Some numbers end up as a happy number (=1); density is 4.2%.
Some numbers end up as 48; density is 4.8%.
More numbers end up in a loop of two (16 and 35); density is 25.4%.
Most numbers end up in a loop of five (9, 81, 63, 27, 45, 9); density is 44.6%.
LINKS
Pieter Post, Table of n, a(n) for n = 1..999
EXAMPLE
a(17)=48 because abs(1^2 - 7^2) = 48 => abs(4^2 - 8^2) = 48.
a(34)=0 because abs(3^2 - 4^2) = 7 => 7^2 = 49 => abs(4^2 - 9^2) = 65 => abs(6^2 - 5^2) = 11 => abs(1^2 - 1^2) = 0.
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Pieter Post, May 09 2015
STATUS
approved