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A170857 a(0) = 0, a(1) = 1; a(2^i + j) = 3a(j) + 3a(j + 1) for 0 <= j < 2^i. 0

%I

%S 0,1,3,12,3,12,45,45,3,12,45,45,45,171,270,144,3,12,45,45,45,171,270,

%T 144,45,171,270,270,648,1323,1242,441,3,12,45,45,45,171,270,144,45,

%U 171,270,270,648,1323,1242,441,45,171,270,270,648,1323,1242,567,648,1323,1620,2754

%N a(0) = 0, a(1) = 1; a(2^i + j) = 3a(j) + 3a(j + 1) for 0 <= j < 2^i.

%H David Applegate, Omar E. Pol and N. J. A. Sloane, <a href="http://neilsloane.com/doc/tooth.pdf">The Toothpick Sequence and Other Sequences from Cellular Automata</a>, 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.]

%H N. J. A. Sloane, <a href="/wiki/Catalog_of_Toothpick_and_CA_Sequences_in_OEIS">Catalog of Toothpick and Cellular Automata Sequences in the OEIS</a>

%K nonn

%O 0,3

%A _N. J. A. Sloane_, Jan 02 2010

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Last modified November 13 10:50 EST 2019. Contains 329093 sequences. (Running on oeis4.)