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A138957
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Concatenation of the reversed digits of numbers from 1 to n.
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7
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1, 12, 123, 1234, 12345, 123456, 1234567, 12345678, 123456789, 12345678901, 1234567890111, 123456789011121, 12345678901112131, 1234567890111213141, 123456789011121314151, 12345678901112131415161
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OFFSET
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1,2
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COMMENTS
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There are no primes in this sequence for n<=7000
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LINKS
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MATHEMATICA
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b = {}; a = {}; Do[w = RealDigits[n]; w = First[w]; Do[AppendTo[a, w[[Length[w] - k + 1]]], {k, 1, Length[w]}]; p = FromDigits[a]; AppendTo[b, p], {n, 1, 21}]; b
(* or *)
Table[FromDigits[Flatten[Reverse/@IntegerDigits[Range[n]]]], {n, 20}] (* Harvey P. Dale, Oct 22 2013 *)
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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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