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Table of n, a(n) for n=1..64.
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
a(n) = 3*A001316(n-1) - 2
Cf. A139250, A139251, A160720, A160721, A160722.
Sequence in context: A205549 A120395 A321078 * A255486 A286779 A007426
Adjacent sequences: A160720 A160721 A160722 * A160724 A160725 A160726
Omar E. Pol, May 25 2009
Formula and more terms from Max Alekseyev, Sep 08 2011