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A222729
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Palindromic composite numbers starting with a digit 9.
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3
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9, 99, 909, 939, 949, 959, 969, 979, 989, 999, 9009, 9119, 9229, 9339, 9449, 9559, 9669, 9779, 9889, 9999, 90009, 90109, 90209, 90309, 90409, 90509, 90609, 90809, 90909, 91119, 91219, 91319, 91419, 91519, 91619, 91719, 91819, 91919, 92029, 92129, 92229, 92329
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listen;
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internal format)
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OFFSET
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1,1
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COMMENTS
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Subsequence of A032350 (palindromic nonprime numbers) and A002113 (palindromic numbers). Complement of A128375 (palindromic primes starting with a digit 9) with respect to A043044 (palindromic numbers starting with a digit 9).
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LINKS
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MATHEMATICA
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Select[Range[100000], PalindromeQ[#]&&CompositeQ[#]&&IntegerDigits[#][[1]] == 9&] (* Harvey P. Dale, Oct 09 2021 *)
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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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