OFFSET
1,2
MATHEMATICA
Nest[Flatten[Join[ #, # /. {1 -> {1, 2}, 2 -> {1, 3}}]] &, {1}, 5] // Flatten
CROSSREFS
KEYWORD
nonn
AUTHOR
Robert G. Wilson v, Jul 27 2006
EXTENSIONS
Name and data corrected by Michel Dekking, Dec 02 2019
STATUS
approved