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A283871
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For all n, the set consisting of the terms {a(1), a(2), a(3), ..., a(n)} has an even number of digits 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9.
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3
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11, 22, 33, 44, 55, 66, 77, 88, 99, 1001, 1010, 1100, 1111, 1122, 1133, 1144, 1155, 1166, 1177, 1188, 1199, 1212, 1221, 1313, 1331, 1414, 1441, 1515, 1551, 1616, 1661, 1717, 1771, 1818, 1881, 1919, 1991, 2002, 2020, 2112, 2121, 2200, 2211, 2222, 2233, 2244, 2255, 2266, 2277, 2288, 2299, 2323, 2332, 2424, 2442, 2525
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OFFSET
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1,1
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COMMENTS
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The sequence is started with a(1) = 11 and always extended with the smallest integer not yet present and not leading to a contradiction.
Numbers that have an even number of each digit 0 to 9. - Robert Israel, Jan 07 2024
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LINKS
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EXAMPLE
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The set consisting of the first 15 terms is {11, 22, 33, 44, 55, 66, 77, 88, 99, 1001, 1010, 1100, 1111, 1122, 1133}; we count there six 0's, sixteen 1's, four 2's, four 3's, etc. All those quantities of digits are even numbers.
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MAPLE
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filter:= proc(n) local L; L:= convert(n, base, 10);
andmap(t -> numboccur(t, L)::even, L) end proc:
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CROSSREFS
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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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