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A222728
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Palindromic composite numbers starting with a digit 7.
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3
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77, 707, 717, 737, 747, 767, 777, 7007, 7117, 7227, 7337, 7447, 7557, 7667, 7777, 7887, 7997, 70007, 70107, 70307, 70407, 70707, 70807, 70907, 71017, 71117, 71217, 71417, 71517, 71617, 71717, 71817, 72027, 72127, 72327, 72427, 72527, 72627, 72827, 72927, 73137
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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 A222727 (palindromic primes starting with a digit 7) with respect to A043042 (palindromic numbers starting with a digit 7).
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LINKS
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MATHEMATICA
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Table[Select[Range[7*10^d, 8*10^d-1], CompositeQ[#]&&PalindromeQ[#]&], {d, 4}]//Flatten (* Harvey P. Dale, Nov 07 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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