From any integer n(0) form n(1) by
concatenating the number of even digits, the number of odd digits and
the sum of digits like this: 129 > (1 even) + (2 odd) + (12 sum) > 1212. Now form n(2) from n(1) in the same way. Eventually, n(n) will be formed where n(n) equals n(m) and m < n. What is the greatest length sequence that can be formed from a 3digit integer? 
The
inset table demonstrates how each successive term is developed. Each
term is the concatenation of the number of even digits, number of odd
digits, and sum of the digits of its predecessor. New terms do not
employ leading zeroes. In this example, line 7 duplicates line 1, so the sequence repeats. 

Site design/maintenance: Dave Ellis Email me!
Last Updated: January 17th, 2010.