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A102544
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Numbers k such that k777777 is prime.
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2
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16, 20, 43, 50, 61, 62, 64, 83, 85, 100, 101, 103, 109, 113, 124, 131, 134, 136, 137, 139, 142, 145, 158, 160, 164, 172, 181, 197, 202, 205, 206, 251, 256, 262, 268, 272, 278, 289, 295, 298, 307, 310, 314, 316, 326, 347, 349, 359, 361, 362, 368, 373, 400, 419, 428, 431, 433, 437, 445
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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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If k=16, then k777777 = 16777777 (prime).
If k=85, then k777777 = 85777777 (prime).
If k=124, then k777777 = 124777777 (prime).
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PROG
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[ n: n in [1..700] | IsPrime(Seqint([7, 7, 7, 7, 7, 7] cat Intseq(n))) ]; // Vincenzo Librandi, Feb 04 2011
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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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