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A164908
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a(n) = (3*4^n - 0^n)/2.
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9
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1, 6, 24, 96, 384, 1536, 6144, 24576, 98304, 393216, 1572864, 6291456, 25165824, 100663296, 402653184, 1610612736, 6442450944, 25769803776, 103079215104, 412316860416, 1649267441664, 6597069766656, 26388279066624, 105553116266496, 422212465065984
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history;
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OFFSET
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0,2
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COMMENTS
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Binomial transform of A164907. Inverse binomial transform of A057651.
Partial sums are in A083420.
Decimal representations of the n-th iterations of elementary cellular automata rules 14, 46, 142 and 174 generate this sequence (see A266298 and A266299). - Karl V. Keller, Jr., Aug 31 2021
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Shalosh B. Ekhad, N. J. A. Sloane, and Doron Zeilberger, A Meta-Algorithm for Creating Fast Algorithms for Counting ON Cells in Odd-Rule Cellular Automata, arXiv:1503.01796 [math.CO], 2015; see also the Accompanying Maple Package.
Shalosh B. Ekhad, N. J. A. Sloane, and Doron Zeilberger, Odd-Rule Cellular Automata on the Square Grid, arXiv:1503.04249 [math.CO], 2015.
N. J. A. Sloane, On the No. of ON Cells in Cellular Automata, Video of talk in Doron Zeilberger's Experimental Math Seminar at Rutgers University, Feb. 05 2015: Part 1, Part 2
N. J. A. Sloane, On the Number of ON Cells in Cellular Automata, arXiv:1503.01168 [math.CO], 2015.
Index entries for sequences related to cellular automata
Index entries for linear recurrences with constant coefficients, signature (4).
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FORMULA
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a(n) = 4*a(n-1) for n > 1; a(0) = 1, a(1) = 6.
G.f.: (1+2*x)/(1-4*x).
a(n) = floor(6*4^(n-1)). - Karl V. Keller, Jr., Aug 30 2021
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MATHEMATICA
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a[n_]:=(MatrixPower[{{2, 2}, {2, 2}}, n].{{2}, {1}})[[2, 1]]; Table[a[n], {n, 0, 40}] (* Vladimir Joseph Stephan Orlovsky, Feb 20 2010 *)
Join[{1}, (3*4^Range[25])/2] (* or *) Join[{1}, NestList[4#&, 6, 25]] (* Harvey P. Dale, Feb 14 2012 *)
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PROG
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(MAGMA) [ (3*4^n-0^n)/2: n in [0..22] ];
(PARI) a(n)=3*4^n\2 \\ Charles R Greathouse IV, Oct 12 2015
(Python) print([int(6*4**(n-1)) for n in range(50)]) # Karl V. Keller, Jr., Aug 30 2021
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CROSSREFS
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Equals 1 followed by A002023 (6*4^n). Essentially the same as A084509.
Cf. A164907, A057651, A083420 (2*4^n-1), A247640, A266298, A266299.
Sequence in context: A253101 A169759 A002023 * A290911 A037505 A048179
Adjacent sequences: A164905 A164906 A164907 * A164909 A164910 A164911
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KEYWORD
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nonn,easy
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AUTHOR
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Klaus Brockhaus, Aug 31 2009
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STATUS
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approved
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