A173458 - OEIS

%I #13 Feb 24 2021 02:48:19

%S 4,6,2,14,18,2,14,18,6,42,54,2,14,18,6,42,54,6,42,54,18,126,162,2,14,

%T 18,6,42,54,6,42,54,18,126,162,6,42,54,18,126,162,18,126,162,54,378,

%U 486,2,14,18,6,42,54,6,42,54,18,126,162,6,42,54,18,126,162

%N a(n) = A173457(n+1)/2.

%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>

%e From Omar E. Pol, Apr 22 2013 (Start):

%e When written as an irregular triangle begins:

%e 4,6;

%e 2,14,18;

%e 2,14,18,6,42,54;

%e 2,14,18,6,42,54,6,42,54,18,126,162;

%e 2,14,18,6,42,54,6,42,54,18,126,162,6,42,54,18,126,162,18, 126,162,54,378,486;

%e 2,14,18,6,42,54,6,42,54,18,126,162,6,42,54,18,126,162,...

%e (End)

%Y Cf. A173456, A173457, A173459, A173462.

%K nonn,tabf

%O 1,1

%A _Omar E. Pol_, Feb 18 2010

%E a(13)-a(65) from _Lars Blomberg_, Apr 22 2013