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A171176
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Triangle read by rows in which row n lists 3n-1 together with the first 2n-1 positive integers, in reverse order.
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9
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2, 1, 5, 3, 2, 1, 8, 5, 4, 3, 2, 1, 11, 7, 6, 5, 4, 3, 2, 1, 14, 9, 8, 7, 6, 5, 4, 3, 2, 1, 17, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 20, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 23, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 26, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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COMMENTS
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a(n) is also the length of the n-th L-toothpick added to the structure of A171166.
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LINKS
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Table of n, a(n) for n=1..90.
N. J. A. Sloane, Catalog of Toothpick and Cellular Automata Sequences in the OEIS
Index entries for sequences related to toothpick sequences
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EXAMPLE
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Triangle begins:
2, 1;
5, 3, 2, 1;
8, 5, 4, 3, 2, 1;
11,7, 6, 5, 4, 3, 2, 1;
14,9, 8, 7, 6, 5, 4, 3, 2, 1;
17,11,10,9, 8, 7, 6, 5, 4, 3, 2, 1;
20,13,12,11,10,9, 8, 7, 6, 5, 4, 3, 2, 1;
23,15,14,13,12,11,10,9, 8, 7, 6, 5, 4, 3, 2, 1;
26,17,16,15,14,13,12,11,10,9, 8, 7, 6, 5, 4, 3, 2, 1;
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CROSSREFS
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Cf. A000027, A016789, A172310, A171164, A161165, A161166, A171172, A171173, A171174, A171175, A171177, A171178.
Cf. A132209 (row sums). [From R. J. Mathar, Mar 01 2010]
Sequence in context: A143409 A197387 A171177 * A213849 A067418 A287548
Adjacent sequences: A171173 A171174 A171175 * A171177 A171178 A171179
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KEYWORD
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easy,nonn,tabf
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AUTHOR
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Omar E. Pol, Feb 23 2010
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STATUS
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approved
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