[go: up one dir, main page]

login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A189668
Fixed point of the morphism 0->010, 1->100.
9
0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1
OFFSET
1
FORMULA
a(3k-2)=a(k), a(3k-1)=1-a(k), a(3k)=0 for k>=1, a(0)=0.
Conjecture: a(n) = 2n - 1 - A285347(n).
This conjecture is correct, and proved in A285347. - Michel Dekking, Sep 07 2022
EXAMPLE
0->010->010100010->
MATHEMATICA
t = Nest[Flatten[# /. {0->{0, 1, 0}, 1->{1, 0, 0}}] &, {0}, 5] (*A189668*)
f[n_] := t[[n]]
Flatten[Position[t, 0]] (*A189669*)
Flatten[Position[t, 1]] (*A189670*)
s[n_] := Sum[f[i], {i, 1, n}]; s[0] = 0;
Table[s[n], {n, 1, 120}] (*A189671*)
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Apr 25 2011
STATUS
approved