Factor-multiple Chains
smallest: 2-4-8-16
largest: 5-25-50-100 produces the largest possible number in the
last three positions but 12-24-48-96 contains the largest number
possible in position one
for example, 26 cannot be in a chain. The latest it can appear is
position two with either 2 or 13 in position one but position four
is limited to a number up to 100 and so cannot offer a value to
make a chain. Also prime numbers must occupy position one in any
chain in which they appear
88 is the maximum difference between adjacent numbers in a chain 2-
4-8-96
For a greatest range 2-4-8-96 looks promising but 5-25-50-100 is
greater still, 95. The minimum range is 14 produced by
2-4-8-16