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Search: id:A138957
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| A138957 |
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Concatenation of the reversed digits of numbers from 1 to n. |
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+0
3
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| 1, 12, 123, 1234, 12345, 123456, 1234567, 12345678, 123456789, 12345678901, 1234567890111, 123456789011121, 12345678901112131, 1234567890111213141, 123456789011121314151, 12345678901112131415161
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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There are no primes in this sequence for n<=7000
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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 (*Artur Jasinski*)
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CROSSREFS
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Cf. A104759, A000422, A116504, A007908, A116505, A104759, A138789, A138790, A138958.
Sequence in context: A057137 A014824 A060555 this_sequence A007908 A057932 A132943
Adjacent sequences: A138954 A138955 A138956 this_sequence A138958 A138959 A138960
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KEYWORD
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nonn,base
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AUTHOR
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Artur Jasinski (grafix(AT)csl.pl), Apr 04 2008, Apr 05 2008
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