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 A170865 a(0) = 1, a(1) = 1; a(2^i + j) = a(j) + 3a(j + 1) for 0 <= j < 2^i. 0

%I

%S 1,1,4,13,4,13,43,25,4,13,43,25,43,142,118,37,4,13,43,25,43,142,118,

%T 37,43,142,118,154,469,496,229,49,4,13,43,25,43,142,118,37,43,142,118,

%U 154,469,496,229,49,43,142,118,154,469,496,229,166,469,496,580,1561,1957,1183

%N a(0) = 1, a(1) = 1; a(2^i + j) = a(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 December 10 04:15 EST 2019. Contains 329885 sequences. (Running on oeis4.)