

A093382


a(n) = length k of longest binary sequence x(1) ... x(k) such that for no n <= i < j <= k/2 is x(i) ... x(2i) a subsequence of x(j) ... x(2j).


6




OFFSET

1,1


COMMENTS

Doesn't the binary sequence 000010011001110011101010101010101010101100110 demonstrate that a(2) >= 45?  R. J. Mathar, Jul 29 2007 Answer: No  see the following comment.
The sequence of length 45 above does not satisfy the requirements of the definition: Subsequences are not required to be consecutive. Therefore it cannot show a(2) >= 45. In the sequence we find for i=2, j=3: x(i..2i) is 000; x(j..2j) is 001001; and 000 is a subsequence of 001001.  Don Reble, May 13 2008


REFERENCES

a(1)  a(3) computed by R. Dougherty, who finds that a(4) >= 187205.


LINKS



EXAMPLE

a(1) = 11 from 01110000000.


CROSSREFS



KEYWORD

nonn,bref,nice,more


AUTHOR



STATUS

approved



