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A308407
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Lexicographically earliest sequence of distinct terms such that reading one-by-one the central pair of digit of each term is the same as reading one-by-one the successive pairs of digits of the sequence itself.
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1
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10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 1110, 1100, 1111, 1000, 1112, 1113, 1101, 1001, 1113, 1120
(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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All terms of the sequence have an even number of digits. For terms having only an odd number of digits, see cross-references.
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LINKS
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EXAMPLE
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The central pair of digits of 10 is 10, of course. The central pair of 1000 is 00. After 99, one reads the successive central pairs 11, 10, 11, 00, 11, 11, 10, 00, 11, 12, ... which are precisely the successive pairs of digits of 1110, 1100, 1111, 1000, 1112, etc.
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CROSSREFS
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Cf. A308406 (the same idea, but with terms having an odd number of digits).
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KEYWORD
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base,nonn
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AUTHOR
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STATUS
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approved
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