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A188068
[nr]-[kr]-[nr-kr], where r=sqrt(3), k=1, [ ]=floor.
10
0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1
OFFSET
1
COMMENTS
Sturmian word with slope alpha = sqrt(3)-1, and offset 0. Since alpha has a periodic continued fraction expansion with period 12, (a(n+1)) is the unique fixed point of the morphism 0 -> 110, 1 -> 1101. - Michel Dekking, Feb 06 2017
A275855(n) = R(a(n)) for n>1, where R is the mirror morphism R(0)=1, R(1)=0, This can be shown by induction on the iterates of the two morphisms generating the sequences. - Michel Dekking, Feb 07 2017
See also A188014.
REFERENCES
J.-P. Allouche and J. Shallit, Automatic Sequences, Cambridge Univ. Press, 2003, p. 286.
FORMULA
a(n) = A007538(n) - 2. [Reinhard Zumkeller, Feb 14 2012]
MATHEMATICA
r=3^(1/2)); k=1;
t=Table[Floor[n*r]-Floor[(n-k)*r]-Floor[k*r], {n, 1, 220}] (*A188068*)
Flatten[Position[t, 0]] (*A188069*)
Flatten[Position[t, 1]] (*A188070*)
PROG
(Haskell)
a188068 = (subtract 2) . a007538 -- Reinhard Zumkeller, Feb 14 2012
(Python)
from gmpy2 import isqrt
def A188068(n):
return int(isqrt(3*n**2) - isqrt(3*(n-1)**2)) - 1 # Chai Wah Wu, Oct 07 2016
CROSSREFS
Cf. A188014.
Sequence in context: A155897 A368915 A144610 * A181632 A105565 A332814
KEYWORD
nonn
AUTHOR
Clark Kimberling, Mar 20 2011
STATUS
approved