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A029975
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Primes that are palindromic in base 7.
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7
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2, 3, 5, 71, 107, 157, 257, 271, 307, 2549, 2647, 2801, 3347, 3697, 3851, 4201, 4397, 4649, 4951, 5399, 5651, 5749, 5903, 6449, 6701, 7451, 7703, 8053, 8501, 8753, 9103, 9551, 10007, 10357, 10903, 11057, 11953, 12157, 12409, 13109
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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f[n_]:=FromDigits[RealDigits[n, 7][[1]]]==FromDigits[Reverse[RealDigits[n, 7][[1]]]]; lst={}; Do[p=Prime[n]; If[f[p], AppendTo[lst, p]], {n, 8!}]; lst (* Vladimir Joseph Stephan Orlovsky, Aug 10 2009 *)
pb7Q[n_]:=Module[{idn7=IntegerDigits[n, 7]}, idn7==Reverse[idn7]]; Select[ Prime[ Range[1600]], pb7Q] (* Harvey P. Dale, Nov 21 2015 *)
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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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