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Search: id:A161830
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| A161830 |
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Y-toothpick triangle (see Comments lines for definition). |
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+0
8
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| 0, 1, 3, 5, 9, 11, 15, 19, 27, 31, 35, 39, 47, 53, 61, 71, 89, 99, 103
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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Y-toothpick sequence starting at the corner of an infinite hexagon in which its vertex touch an endpoint of the initial Y-toothpick and the two other endpoints are equidistant from the nearest sides of the hexagon.
The sequence gives the number of Y-toothpicks in the sieve after n rounds. A161831 (the first differences) gives the number added at the nth round.
See the Y-toothpick sequence A160120 for more information about the recursive, fractal-like structure.
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CROSSREFS
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Cf. A139250, A160120, A160121, A160406, A160407, A161831, A161832, A161833.
Sequence in context: A075991 A002731 A006046 this_sequence A151922 A104635 A024903
Adjacent sequences: A161827 A161828 A161829 this_sequence A161831 A161832 A161833
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KEYWORD
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more,nonn
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AUTHOR
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Omar E. Pol (info(AT)polprimos.com), Jun 20 2009
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