A171170 Corner sequence (starting each round in the first quadrant).

1, 2, 3, 4, 4, 1, 2, 1, 2, 3, 2, 3, 4, 3, 4, 1, 4, 1, 2, 1, 2, 3, 2, 3, 4, 3, 4, 1, 3, 4, 1, 4, 1, 2, 1, 2, 3, 4, 1, 2, 1, 2, 3, 2, 3, 4, 1, 2, 3, 2, 3, 4, 3, 4, 1, 2, 3, 4, 3, 4, 1, 4, 1, 2, 4, 1, 2, 1, 2, 3, 2, 3, 4, 3, 4, 1, 3, 4, 1, 4, 1, 2, 1, 2, 3, 4, 1, 2, 1, 2, 3, 2, 3, 4, 1, 2, 3, 2, 3, 4, 3, 4, 1, 2, 3

Offset: 1

Author

Omar E. Pol, Dec 04 2009

Keywords

• nonn
• tabf

Comments

See A161411, which is the main entry for this sequence.

See also A171171 for another version.

Examples

			================
.......41.......
.......32.......
================
......4141......
......3..2......
......4..1......
......3232......
================
.....41..41.....
.....3....2.....
................
................
.....4....1.....
.....32..32.....
================
....41414141....
....3..23..2....
....4......1....
....32....32....
....41....41....
....3......2....
....4..14..1....
....32323232....
================
...41......41...
...3........2...
................
................
................
................
................
................
................
...4........1...
...32......32...
================
And so on.
Triangle begins:
1,2,3,4;
4,1,2, 1,2,3, 2,3,4, 3,4,1;
4,1,2, 1,2,3, 2,3,4, 3,4,1;
3,4,1,4,1,2,1,2,3, 4,1,2,1,2,3,2,3,4, 1,2,3,2,3,4,3,4,1, 2,3,4,3,4,1,4,1,2;
4,1,2, 1,2,3, 2,3,4, 3,4,1;
3,4,1,4,1,2,1,2,3, 4,1,2,1,2,3,2,3,4, 1,2,3,2,3,4,3,4,1, 2,3,4,3,4,1,4,1,2;
Contribution from _Omar E. Pol_, Dec 09 2009: (Start)
Illustration for n = 1..148
================
.41..41..41..41.
.341412..341412.
..3412....3412..
..434141414121..
.43234123412321.
.32.43414121.32.
....32341232....
....41432141....
.41.34323212.41.
.34143214321412.
..343232323212..
..4321....4321..
.432321..432321.
.32..32..32..32.
================
(End)
		

Links

• 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

Crossrefs

Cf. A139250, A139251, A160410, A161411, A171171.