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Search: id:A120442
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| A120442 |
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P-positions of John H. Conway's "Digit Deletions" game from _On Numbers And Games_. Each number is the smallest positive integer that cannot be reduced to an earlier number in the sequence, by performing one of the following two operations: - changing one digit to a smaller digit (but not changing the leading digit to 0); - deleting a 0 and all subsequent digits. |
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+0
1
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| 1, 11, 20, 32, 43, 54, 65, 76, 87, 98, 111, 120, 132, 143, 154, 165, 176, 187, 198, 201, 210, 222, 233, 244, 255, 266, 277, 288, 299, 300, 312, 321, 334, 345, 353, 367, 378, 386, 402, 413, 424, 431, 440, 456, 468, 475, 489, 497, 503, 514
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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The sequence is base-dependent, but notice that each number in a given base's sequence has a correspondent in all higher bases (the number with the same digit representation). The smallest n-digit number in the sequence is always a repunit.
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REFERENCES
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John H. Conway, _On Numbers and Games_, 2nd Edition, pp. 190-192.
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EXAMPLE
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201 is in the sequence because every number it may be reduced to (101, 2, 200) is not in the sequence: 101 and 2 both reduce to 1, and 200 reduces to 20.
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CROSSREFS
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Sequence in context: A044054 A044435 A011753 this_sequence A059407 A109376 A100038
Adjacent sequences: A120439 A120440 A120441 this_sequence A120443 A120444 A120445
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KEYWORD
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base,easy,nonn
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AUTHOR
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Trevor Green (green(AT)math.usask.ca), Jul 18 2006
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