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A170907 Row sums in triangle A170906. 5

%I #9 Feb 24 2021 02:48:19

%S 1,4,8,13,20,28,37,47,59,73,87,101,118,137,156,176,198,223,248,271,

%T 299,328,357,386,418,454,489,522,558,598,638,678,720,766,812,858,907,

%U 956,1004,1048,1104,1161,1217,1268,1325,1386,1446,1505,1567,1635,1703,1765

%N Row sums in triangle A170906.

%C Total number of cells that get turned ON in the n-th 30-60-90 triangle of hexagons described in A170906.

%C I wish I had a recurrence for this sequence!

%H David Applegate, <a href="/A170907/b170907.txt">Table of n, a(n) for n = 1..5989</a>

%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 Cf. A170906, A169757, A169758, A163862 (values at powers of 2).

%K nonn

%O 1,2

%A _N. J. A. Sloane_, Jan 24 2010

%E More terms from _R. J. Mathar_, Jan 28 2010

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Last modified March 29 10:22 EDT 2024. Contains 371268 sequences. (Running on oeis4.)