OFFSET
0,3
COMMENTS
Essentially the first differences of A173460.
It appears that row lengths give the absolute values of A110164. - Omar E. Pol, Apr 25 2013
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
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]
EXAMPLE
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)
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Omar E. Pol, Feb 18 2010
EXTENSIONS
More terms a(14)-a(17) from Omar E. Pol, Sep 25 2011
a(18)-a(58) from Lars Blomberg, Apr 23 2013
STATUS
approved