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A302500
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Lexicographically first sequence of distinct terms such that any set of five successive digits can be reordered as {d, d+1, d+2, d+3, d+4}, d being the smallest of the five digits.
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5
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0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 56, 78, 45, 67, 34, 562, 345, 12, 340, 123, 40, 1234, 51, 23, 401, 234, 512, 3401, 2340, 12340, 12345, 62, 3451, 2345, 623, 451, 23401, 23451, 23456, 73, 456, 734, 567, 84, 5673, 4562, 3456, 784, 5678, 95, 678, 956, 789, 56784, 56734, 5623, 4512, 34012, 34512, 34562, 34567, 89
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OFFSET
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1,3
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COMMENTS
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As the digit 0 has no predecessor and the digit 9 has no successor here, sets of successive digits like {3,2,1,0,9} and {6,7,8,9,0} are forbidden.
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LINKS
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EXAMPLE
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Terms a(1) to a(10) are obvious;
a(11) is 56 because 56 is the smallest integer not yet in the sequence such that the elements of the sets {6,7,8,9,5} and {7,8,9,5,6} are five consecutive digits;
a(12) is 78 because 78 is the smallest integer not yet in the sequence such that the elements of the sets {8,9,5,6,7} and {9,5,6,7,8} are five consecutive digits;
a(13) is 45 because 45 is the smallest integer not yet in the sequence such that the elements of the sets {5,6,7,8,4} and {6,7,8,4,5} are five consecutive digits;
etc.
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CROSSREFS
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Cf. A228326 for the same idea with sets of two digits, A302173 for sets of three digits and A302499 for sets of four digits.
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KEYWORD
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nonn,base
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AUTHOR
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STATUS
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approved
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