login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A170903 a(n) = 2*A160552(n)-1. 6
1, 1, 5, 1, 5, 9, 13, 1, 5, 9, 13, 9, 21, 33, 29, 1, 5, 9, 13, 9, 21, 33, 29, 9, 21, 33, 37, 41, 77, 97, 61, 1, 5, 9, 13, 9, 21, 33, 29, 9, 21, 33, 37, 41, 77, 97, 61, 9, 21, 33, 37, 41, 77, 97, 69, 41, 77, 105, 117, 161, 253, 257, 125, 1, 5, 9, 13, 9, 21, 33, 29, 9, 21, 33, 37, 41, 77 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..77.

David Applegate, Omar E. Pol and N. J. A. Sloane, The Toothpick Sequence and Other Sequences from Cellular Automata, Congressus Numerantium, Vol. 206 (2010), 157-191. [There is a typo in Theorem 6: (13) should read u(n) = 4.3^(wt(n-1)-1) for n >= 2.]

N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS

FORMULA

It appears that a(n) = A160164(n) - A169707(n). - Omar E. Pol, Feb 17 2015

EXAMPLE

When written as a triangle:

1

1, 5;

1, 5, 9, 13;

1, 5, 9, 13, 9, 21, 33, 29;

...

Rows sums are A006516 (this is immediate from the definition).

From Omar E. Pol, Feb 17 2015: (Start)

Also, written as an irregular triangle in which the row lengths are the terms of A011782:

1;

1;

5,1;

5,9,13,1;

5,9,13,9,21,33,29,1;

5,9,13,9,21,33,29,9,21,33,37,41,77,97,61,1;

5,9,13,9,21,33,29,9,21,33,37,41,77,97,61,9,21,33,37,41,77,97,69,41,77,105,117,161,253,257,125,1;

Row sums give 1 together with the positive terms of A006516.

It appears that the right border (A000012) gives the smallest difference between A160164 and A169707 in every period.

(End)

CROSSREFS

Cf. A006516, A139250, A139251, A160164, A160552, A169707.

Sequence in context: A103986 A196404 A128359 * A319663 A255166 A131113

Adjacent sequences:  A170900 A170901 A170902 * A170904 A170905 A170906

KEYWORD

nonn

AUTHOR

Gary W. Adamson, Jan 21 2010

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 15 01:22 EST 2019. Contains 329142 sequences. (Running on oeis4.)