Palindromic Binary Sequence (again?)
Leroy Quet
qq-quet at mindspring.com
Sun Feb 22 21:43:19 CET 2004
I may have posted the below to seq.fan almost a year ago already, but I
cannot recall.
In any case, the sequence of 1's and 0's is not in the EIS, so perhaps I
did not post this before. (yet I did not use Superseeker.)
(I apologize if this is a repost here.)
Consider the sequence of 1's and 0's which is "super-palindromic", and
has an interesting property if converted to a binary-represented real.
Let each A be a finite sequence of 0's and 1's,
where:
A(1) = 1;
for k >= 2,
A(k) = A(k-1) A(k-1) , if a(k-1) = 0;
A(k) = A(k-1) 0 A(k-1) , if a(k-1) = 1;
where the sequences A(k) are concatenations involving A(k-1),
and a(k) is the k_th term of the sequence
limit{k->oo} A(k).
The sequence begins:
1,0,1,1,0,1,0,1,0,1,1,0,1,0,1,0,1,1,0,1,0,1,0,1,1,0,1,
1,0,1,1,0,1,0,1,0,1,1,0,1,0,1,0,1,1,0,1,0,1,0,1,1,0,1,...
(Interesting in that the sequence is not only palindromic, but HOW it is
palindromic is also palindromic {in a recursive manner}.)
Now, consider the real x, where
x = sum{k=1 to oo} a(k)/2^k,
the binary-represented x having the k_th digit right of the decimal-point
(the binary-point?) equal to a(k).
ie.
x = .101101010110101011010101101...
Then the ratio of number of 0's in this total sequence ("total sequence"
= the limit of A(k) as k approaches infinity) to the number of 1's in
this total sequence is...
x.
---
There is at least one other real, y, with the ratio-property: its binary
representaion has a ratio of
y = (number of 0's in binary representation)
/(number of 1's in binary representation).
Even though it is not palindromic, the y-sequence can be generated in a
similar manner to the x-sequence.
B(1) = 1;
for k >= 2,
B(k) = B(k-1) B(k-1) , if b(k-1) = 0;
B(k) = B(k-1) B(k-1) 0 , if b(k-1) = 1;
b(k) = k_th element of {limit k-> oo} B(k).
(I think this is right...)(??)
What is known about all reals with the "ratio property"?
thanks,
Leroy Quet
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