An addition chain for a number is a Sequence
, such that each member after
is the Sum of two earlier (not necessarily distinct) ones. The number is called the length of the
addition chain. For example,
See also Brauer Chain, Hansen Chain, Scholz Conjecture
Guy, R. K. ``Addition Chains. Brauer Chains. Hansen Chains.'' §C6 in
Unsolved Problems in Number Theory, 2nd ed. New York: Springer-Verlag,
pp. 111-113, 1994.