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Search: id:A060546
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| A060546 |
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a(n) is the number of median-reflective (palindrome) symmetric patterns in a top-down equilateral triangular arrangement of closely packed black and white cells satisfying the local matching rule of Pascal's triangle modulo 2, where n is the number of cells in each edge of the arrangement. The matching rule is such that any elementary top-down triangle of three neighboring cells in the arrangement contains either one or three white cells. |
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+0
8
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| 2, 2, 4, 4, 8, 8, 16, 16, 32, 32, 64, 64, 128, 128, 256, 256, 512, 512, 1024, 1024, 2048, 2048, 4096, 4096, 8192, 8192, 16384, 16384, 32768, 32768, 65536, 65536, 131072, 131072, 262144, 262144, 524288, 524288, 1048576, 1048576, 2097152, 2097152
(list; graph; listen)
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OFFSET
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1,1
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REFERENCES
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A. Barb\'{e}, Symmetric patterns in the cellular automaton that generates Pascal's triangle modulo 2, Discr. Appl. Math. 105(2000), 1-38.
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LINKS
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Harry J. Smith, Table of n, a(n) for n=1,...,500
Index entries for sequences related to cellular automata
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FORMULA
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a(n) =2^ceil(n/2)
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MAPLE
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for n from 1 to 100 do printf(`%d, `, 2^ceil(n/2)) od:
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PROGRAM
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(PARI) { for (n=1, 500, write("b060546.txt", n, " ", 2^ceil(n/2)); ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Jul 06 2009]
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CROSSREFS
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a(n)=A016116(n+1) for n >= 1 a(n)=2^A008619(n-1) for n >= 1
Adjacent sequences: A060543 A060544 A060545 this_sequence A060547 A060548 A060549
Sequence in context: A117575 A152166 A016116 this_sequence A163403 A120803 A000011
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KEYWORD
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easy,nice,nonn
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AUTHOR
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Andr\'{e} Barb\'{e} (Andre.Barbe(AT)esat.kuleuven.ac.be), Apr 03 2001
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EXTENSIONS
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More terms from James A. Sellers (sellersj(AT)math.psu.edu), Apr 04 2001
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