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A062231
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Numbers k such that the smoothly undulating palindromic number (97*10^k - 79)/99 is a prime.
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1
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OFFSET
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1,1
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COMMENTS
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Prime versus probable prime status and proofs are given in the author's table.
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LINKS
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EXAMPLE
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k=27 -> (97*10^27 - 79)/99 = 979797979797979797979797979.
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MATHEMATICA
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Select[Range[1, 239, 2], PrimeQ[FromDigits[PadRight[{}, #, {9, 7}]]]&] (* Harvey P. Dale, Mar 24 2021 *)
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CROSSREFS
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KEYWORD
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nonn,base,more
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AUTHOR
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Patrick De Geest and Hans Rosenthal (Hans.Rosenthal(AT)t-online.de), Jun 15 2001
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EXTENSIONS
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STATUS
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approved
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