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a(n) = A153006(n)*3.
2

%I #9 Feb 24 2021 02:48:18

%S 0,3,9,18,27,39,60,84,99,111,132,159,189,234,300,360,387,399,420,447,

%T 477,522,588,651,693,738,807,891,996,1152,1344,1488,1539,1551,1572,

%U 1599,1629,1674,1740,1803,1845,1890,1959,2043,2148,2304,2496,2643

%N a(n) = A153006(n)*3.

%H David Applegate, Omar E. Pol and N. J. A. Sloane, <a href="/A000695/a000695_1.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>

%Y Toothpick sequence: A139250.

%Y Cf. A139251, A152980, A153006, A159793, A159795.

%K nonn

%O 0,2

%A _Omar E. Pol_, May 02 2009

%E More terms from _Max Alekseyev_, Dec 13 2011