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A064829
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Smallest number greater than 1 which ends in an odd digit in bases 2 through n.
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0
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3, 7, 7, 13, 13, 31, 31, 43, 43, 73, 73, 271, 271, 271, 271, 313, 313, 313, 313, 313, 313, 421, 421, 421, 421, 1303, 1303, 1303, 1303, 1303, 1303, 23563, 23563, 35803, 35803, 187003, 187003, 187003, 187003, 936703, 936703, 1426003, 1426003, 1426003, 1426003
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OFFSET
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2,1
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LINKS
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EXAMPLE
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13 = 1101 in base 2, 231 in base 3, 31 in base 4, 23 in base 5, 21 in base 6 but 16 in base 7, so 13 ends in an odd digit from bases 2 to 6.
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MAPLE
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a:= proc(n) option remember; local k; for k by 2 from `if`(n=2, 3,
a(n-1)) while ormap(b-> irem(k, b)::even, [$2..n]) do od; k
end:
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MATHEMATICA
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a[n_] := Module[{k = 3}, While[!AllTrue[Range[2, n], OddQ[Mod[k, #]] &], k += 2]; k]; Array[a, 45, 2] (* Amiram Eldar, Jul 30 2023 *)
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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Jonathan Ayres (jonathan.ayres(AT)btinternet.com), Oct 23 2001
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EXTENSIONS
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STATUS
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approved
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