OFFSET
1,1
COMMENTS
The sequence is based on a table of shortest addition chain lengths computed by Neill M. Clift, see link to Achim Flammenkamp's web page given at A003313.
LINKS
Hugo Pfoertner, Table of n, a(n) for n = 1..10000
EXAMPLE
a(1)=8719 because this is the smallest number for which the addition chain produced by the power tree method [1 2 3 5 7 14 28 56 61 117 234 468 936 1872 3744 3861 7722 7783 8719] is by two terms longer than the shortest possible chains for this number. An example of such a chain is [1 2 3 6 9 15 17 34 68 136 272 544 1088 2176 4352 4367 8719].
CROSSREFS
Cf. A114622 [The power tree (as defined by Knuth)], A003313 [Length of shortest addition chain for n], A113945 [numbers such that Knuth's power tree method produces a result deficient by 1], A115615 [numbers such that Knuth's power tree method produces a result deficient by 3], A115616 [smallest number for which Knuth's power tree method produces an addition chain n terms longer than the shortest possible chain].
KEYWORD
nonn
AUTHOR
Hugo Pfoertner and Neill M. Clift, Feb 15 2006
STATUS
approved