OFFSET

0,2

COMMENTS

This is different from a straight-line program (SLP), which can only use numbers created in the path to its own result at level n-1. A288849 provides the cardinalities of the sets that can be created by the related SLPs.

EXAMPLE

The sets of numbers obtainable at the n-th step are:

S(0) = { 1 },

S(1) = { 0, 1, 2 },

S(2) = { -2, -1, 0, 1/2, 1, 2, 3, 4 },

S(3) = { -8, -6, -5, -4, -7/2, -3, -5/2, -2, -3/2, -1, -2/3, -1/2, -1/3, -1/4, 0, 1/8, 1/6, 1/4, 1/3, 1/2, 2/3, 3/4, 1, 4/3, 3/2, 2, 5/2, 3, 7/2, 4, 9/2, 5, 6, 7, 8, 9, 12, 16 }.

CROSSREFS

KEYWORD

nonn,more,hard

AUTHOR

Hugo Pfoertner, Jun 15 2017

EXTENSIONS

a(6) from Hugo Pfoertner and Markus Sigg, Aug 06 2017

STATUS

approved