A160123 a(n) = A160121(n+1)/3.

1, 1, 3, 1, 3, 3, 7, 3, 3, 3, 7, 5, 7, 9, 17, 9, 3, 3, 7, 5, 7, 9, 17, 11, 7, 9, 17, 17, 19, 23, 39, 27, 7, 3, 7, 5, 7, 9, 17, 11, 7, 9, 17, 17, 19, 23, 39, 29, 11, 9, 17, 17, 19, 25, 43, 39, 25, 23, 39, 45, 47, 57, 93, 77, 23, 3, 7, 5, 7, 9

Offset

1,3

Comments

Also, first differences of A161910. [From Omar E. Pol, Jun 21 2009]

Links

Table of n, a(n) for n=1..70.

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

Example

Note that this can be written as a triangle:
1;
1;
3;
1,3;
3,7,3,3;
3,7,5,7,9,17,9,3;
3,7,5,7,9,17,11,7,9,17,17,19,23,39,27,7;
3,7,5,7,9,17,11,7,9,17,17,19,23,39,29,11,9,17,17,19,25,43,39,25,23,39,45,47,57,93,77,23;
3,7,5,7,9,...

Crossrefs

Y-toothpick sequence: A160120. Cf. A160121, A160122.

Cf. A139250, A139251. [From Omar E. Pol, Jun 16 2009]

Cf. A161831, A161427, A161910. [From Omar E. Pol, Jun 21 2009]

Sequence in context: A331856 A163381 A327190 * A238784 A336765 A147610

Adjacent sequences: A160120 A160121 A160122 * A160124 A160125 A160126

Keyword

nonn

Author

Omar E. Pol, May 02 2009, May 21 2010

Extensions

More terms from Omar E. Pol, Jun 16 2009

Extended by R. J. Mathar, Feb 05 2010

Status

approved