A100588 Numerical value of the following string operation iterated n-1 times on the string "1": (1) Concatenate "0" to the left and to the right to the old string and initialize a new string. (2) Scan the old string from left to right. Whenever "00" occurs in the old string, write "0" to the new string; whenever "01" or "10" occurs in the old string, write "1" to the new string; whenever "11" occurs in the old string, write "10" to the new string.

1, 3, 13, 55, 885, 14175, 3628885, 928994815, 60882604217685, 3990002350010269695, 17136929604257253605596550485

Offset

0,2

Links

Table of n, a(n) for n=0..10.

Example

Applying the operation to the initial string "1" gives us "11". Subsequent iterations give us "1101" and "110111". The numerical values corresponding to the binary strings "1," "11," "1101," and "110111" are, of course, 1, 3, 13 and 55.

Crossrefs

Sequence in context: A151218 A151219 A006225 * A081952 A234645 A010920

Adjacent sequences: A100585 A100586 A100587 * A100589 A100590 A100591

Keyword

nonn

Author

George J. Schaeffer (gschaeff(AT)andrew.cmu.edu), Jan 02 2005

Status

approved