A170903 a(n) = 2*A160552(n)-1.

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

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: A196404 A128359 A340213 * A319663 A255166 A131113

Adjacent sequences: A170900 A170901 A170902 * A170904 A170905 A170906

Keyword

nonn

Author

Gary W. Adamson, Jan 21 2010

Status

approved