A173461 Number of cells turned "ON" at n-th stage of cellular automaton of A173460.

0, 1, 8, 12, 8, 52, 12, 12, 84, 36, 28, 188, 12, 12, 84, 36, 36, 252, 36, 36, 252, 108, 92, 628, 12, 12, 84, 36, 36, 252, 36, 36, 252, 108, 108, 756, 36, 36, 252, 108, 108, 756, 108, 108, 756, 324, 292, 2012, 12, 12, 84, 36, 36, 252, 36, 36, 252, 108, 108

Offset: 0

Author

Omar E. Pol, Feb 18 2010

Keywords

• nonn
• tabf

Comments

Essentially the first differences of A173460.

It appears that row lengths give the absolute values of A110164. - Omar E. Pol, Apr 25 2013

Examples

			From _Omar E. Pol_, Apr 25 2013: (Start)
When written as an irregular triangle begins:
0;
1,8;
12,8,52;
12,12,84,36,28,188;
12,12,84,36,36,252,36,36,252,108,92,628;
12,12,84,36,36,252,36,36,252,108,108,756,36,36,252,108,108,756,108,108,756,324,292,2012;
12,12,84,36,36,252,36,36,252,108,108,...
(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, A173457, A173460, A173462, A173463.

Formula

a(0)=0, a(1)=1, a(2)=8, for n>=3 let i=n/3+1, j=A147610(i), if 2^r==i for some r then let c1=2^(r+1), c2=2^(r+4) else let c1=c2=0, finally when (n MOD 3)=0,1,2 let a(n)=12*j, 12*j-c1, 84*j-c2. (Found empirically) [Lars Blomberg, Apr 23 2013]

Extensions

More terms a(14)-a(17) from Omar E. Pol, Sep 25 2011

a(18)-a(58) from Lars Blomberg, Apr 23 2013