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A102606
Numbers k such that 1kkk1 is prime.
3
3, 5, 6, 9, 18, 21, 24, 25, 26, 36, 39, 41, 42, 49, 53, 54, 58, 59, 64, 65, 69, 71, 72, 79, 87, 91, 93, 105, 124, 132, 155, 159, 162, 163, 165, 168, 172, 184, 187, 196, 210, 214, 221, 226, 235, 238, 249, 256, 272, 278, 284, 289, 312, 323, 327, 329, 331, 336, 341, 342
OFFSET
1,1
LINKS
EXAMPLE
If k=3, then 13331 is prime.
If k=39, then 13939391 is prime.
If k=65, then 16565651 is prime.
MATHEMATICA
Select[Range[360], PrimeQ[FromDigits[Flatten[IntegerDigits /@ {1, #, #, #, 1}]]] &]
CROSSREFS
Sequence in context: A176345 A101139 A309140 * A102372 A095829 A054871
KEYWORD
nonn,base
AUTHOR
Parthasarathy Nambi, Jan 29 2005
EXTENSIONS
Extended by Ray Chandler, Jan 30 2005
STATUS
approved