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Search: id:A068702
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| A068702 |
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Numbers n such that concatenation n^2, n and 1 is a prime. |
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+0
4
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| 2, 5, 8, 9, 17, 27, 32, 39, 41, 56, 60, 65, 66, 68, 72, 78, 89, 98, 108, 117, 120, 128, 132, 159, 168, 173, 176, 191, 192, 194, 197, 209, 212, 213, 246, 248, 254, 264, 272, 282, 288, 293, 296, 302, 311, 315, 324, 327, 332, 341, 350, 353, 360, 371, 392, 425, 444
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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8 is a member, as the concatenation of 8^2, 8 and 1 i.e. 6481 is a prime.
32 is a member as 1024321 (concatenation of 32^2, 32 and 1) is prime.
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MATHEMATICA
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Select[ Range[457], PrimeQ[ FromDigits[ Join[ IntegerDigits[ #^2], IntegerDigits[ # ], IntegerDigits[ #^0]]] &]
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CROSSREFS
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Cf. A088619, A068701.
Sequence in context: A026448 A050678 A088620 this_sequence A083724 A072476 A078345
Adjacent sequences: A068699 A068700 A068701 this_sequence A068703 A068704 A068705
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KEYWORD
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base,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Mar 04 2002
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EXTENSIONS
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More terms from Jason Earls (jcearls(AT)cableone.net), Jun 10 2002
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