OFFSET
1,2
COMMENTS
See A189727.
This sequence also gives the positions of 0 in the fixed point of the morphism 0->012, 1->210, 2->120. Moreover, a(n) - a(n-1) is in {1,3,5} for n >= 1; also, 3n - a(n) is in {0, 2} for n >= 1. The first 20 numbers 3n - a(n) are 2, 0, 0, 0, 0, 2, 0, 0, 2, 0, 0, 2, 0, 0, 2, 2, 0, 0, 0, 0, with 2 in positions given by A189728. - Clark Kimberling, May 25 2017
LINKS
Clark Kimberling, Table of n, a(n) for n = 1..10000
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Apr 26 2011
STATUS
approved