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A089377
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Numbers whose product of digits +1 and -1 gives twin prime pairs.
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2
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4, 6, 14, 16, 22, 23, 26, 29, 32, 34, 36, 41, 43, 56, 61, 62, 63, 65, 67, 76, 89, 92, 98, 114, 116, 122, 123, 126, 129, 132, 134, 136, 141, 143, 156, 161, 162, 163, 165, 167, 176, 189, 192, 198, 212, 213, 216, 219, 221, 223, 231, 232, 233, 235, 237, 249, 253, 256
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OFFSET
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1,1
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LINKS
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EXAMPLE
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36 is a member since 3*6 = 18 and (17,19) is a twin prime pair.
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MATHEMATICA
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prodDig[n_] := Times @@ IntegerDigits[n]; Select[Range[256], And @@ PrimeQ [prodDig[#] + {-1, 1}] &] (* Amiram Eldar, Dec 27 2019 *)
Select[Range[300], AllTrue[Times@@IntegerDigits[#]+{1, -1}, PrimeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 26 2021 *)
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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