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A057628
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Primes such that replacing each digit d with d copies of the digit d produces a prime. Zeros are not allowed.
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3
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11, 31, 53, 131, 149, 223, 283, 311, 313, 331, 397, 463, 641, 691, 937, 941, 1439, 1511, 1741, 1871, 1949, 1993, 1999, 2111, 2447, 2939, 3163, 3391, 3433, 3499, 3559, 3593, 3659, 3911, 3931, 5227, 5399, 5923, 6163, 6269, 6653, 6719, 7177, 7741, 8389
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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EXAMPLE
| E.g. 641 becomes 66666644441 which is also prime.
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MATHEMATICA
| Select[Prime[Range[1500]], PrimeQ[FromDigits[Flatten[Table[#, {#}]&/@ IntegerDigits[#]]]]&&DigitCount[#, 10, 0]==0&] (* From Harvey P. Dale, Mar 27 2011 *)
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CROSSREFS
| Cf. A057630.
Sequence in context: A152293 A031287 A057630 * A144364 A031372 A028877
Adjacent sequences: A057625 A057626 A057627 * A057629 A057630 A057631
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KEYWORD
| nonn,base,nice,easy
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AUTHOR
| G. L. Honaker, Jr. (honak3r(AT)gmail.com), Oct 10 2000
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EXTENSIONS
| More terms from Patrick De Geest (pdg(AT)worldofnumbers.com), Oct 15 2000.
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