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A110054
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Numbers n such that the string 222n is the decimal expansion of a prime number.
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1
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1, 29, 47, 59, 71, 73, 77, 79, 83, 91, 107, 109, 113, 127, 137, 149, 151, 161, 163, 193, 197, 199, 247, 269, 289, 293, 311, 317, 323, 329, 337, 347, 349, 361, 367, 379, 389, 403, 419, 437, 461, 493, 499, 511, 527, 533, 553, 557, 587, 601, 613, 619, 643, 647
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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EXAMPLE
| 1 is in the sequence because 2221 is prime.
91 is in the sequence because 22291 is prime.
109 is in the sequence because 222109 is prime.
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MATHEMATICA
| Select[Range[1000], PrimeQ[FromDigits[Join[{2, 2, 2}, IntegerDigits[ # ]]]] &] (* Alonso Delarte *)
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PROG
| (MAGMA) [ n: n in [1..700] | IsPrime(Seqint(Intseq(n) cat [2, 2, 2])) ]; // Klaus Brockhaus, Feb 03 2011
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CROSSREFS
| Sequence in context: A108280 A077782 A059414 * A104912 A104913 A102852
Adjacent sequences: A110051 A110052 A110053 * A110055 A110056 A110057
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KEYWORD
| nonn,base
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AUTHOR
| Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Sep 04 2005
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EXTENSIONS
| More terms from Alonso Delarte (alonso.delarte(AT)gmail.com), Sep 06 2005
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