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A065437
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Smallest base relative to which the n-th prime is palindromic.
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1
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3, 2, 2, 2, 10, 3, 2, 18, 3, 4, 2, 6, 5, 6, 46, 52, 4, 6, 5, 7, 2, 78, 5, 8, 8, 10, 102, 2, 5, 8, 2, 10, 136, 138, 148, 3, 7, 162, 166, 3, 178, 10, 6, 12, 6, 11, 8, 222, 8, 12, 3, 14, 12, 8, 2, 262, 268, 7, 11, 14, 282, 292, 7, 310, 2, 316, 15, 9, 346, 8, 10, 358, 366, 4, 13, 10, 388
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OFFSET
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1,1
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COMMENTS
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LINKS
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EXAMPLE
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71 is the 20th prime and can be written as 131 in base 7, hence a(20)=7.
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MATHEMATICA
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PrimeMinBase[ n_ ] := NestWhile[ # + 1 &, 2, IntegerDigits[ Prime[ n ], # ] != Reverse[ IntegerDigits[ Prime[ n ], # ] ] & ]
sbr[n_]:=Module[{k=2}, While[IntegerDigits[n, k]!=Reverse[ IntegerDigits[ n, k]], k++]; k]; Table[sbr[n], {n, Prime[Range[80]]}] (* Harvey P. Dale, Jun 07 2016 *)
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CROSSREFS
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KEYWORD
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base,easy,nonn
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AUTHOR
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Peter Bertok (peter(AT)bertok.com), Nov 23 2001
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STATUS
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approved
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