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Search: id:A102606
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A102606 Numbers n such that 1nnn1 is prime. +0
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 (list; graph; listen)
OFFSET

1,1

EXAMPLE

If n=3, then 13331 is prime.

If n=39, then 13939391 is prime.

If n=65, then 16565651 is prime.

MATHEMATICA

Select[Range[360], PrimeQ[FromDigits[Flatten[IntegerDigits /@ {1, #, #, #, 1}]]] &]

CROSSREFS

Cf. A102607, A102608.

Sequence in context: A070111 A070117 A101139 this_sequence A102372 A095829 A065512

Adjacent sequences: A102603 A102604 A102605 this_sequence A102607 A102608 A102609

KEYWORD

nonn,base

AUTHOR

Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Jan 29 2005

EXTENSIONS

Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Jan 30 2005

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Last modified December 13 23:45 EST 2009. Contains 170824 sequences.


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