OFFSET
1
COMMENTS
It seems likely that this is the same sequence as A288932 without its leading 0, but the two definitions are so different that it is worth having both versions.
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
M. Bucci, A. De Luca, A. Glen, and L. Q. Zamboni, A connection between palindromic and factor complexity using return words, arXiv:0802.1332 [math.CO], 2008. See Section 4.
A. Glen, J. Justin, S. Widmer, L. Q. Zamboni, Palindromic richness, arXiv:0801.1656 [math.CO], 2008.
MAPLE
f:= 'f':
f(0):= (0, 1, 0, 1):
f(1):= 1:
A:= [0]:
for i from 1 to 9 do A:= map(f, A) od:
A; # Robert Israel, Jun 05 2019
MATHEMATICA
Nest[Flatten[ReplaceAll[#, 0->{0, 1, 0, 1}]]&, {0}, 6] (* Paolo Xausa, Nov 08 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Jun 05 2019
STATUS
approved