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Search: id:A087368
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| A087368 |
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Prime index primes (PIPS) whose digits are primes. |
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+0
1
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| 3, 5, 277, 353, 773, 3733, 5557, 7523, 7753, 25357, 25733, 27733, 32233, 32323, 32533, 37273, 53233, 53353, 53377, 53777, 55733, 72337, 72727, 73757, 77377, 77557, 232523, 272333, 275773, 322727, 327553, 327757, 333233, 352357, 353527
(list; graph; listen)
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OFFSET
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3,1
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COMMENT
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Chances are these numbers are infinite since PIPS are infinite.
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LINKS
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A. Frank & P. Jacqueroux, International Contest, 2001. Item 12
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EXAMPLE
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59 is prime and the 59th prime is 277 and 2,7 are primes.
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PROGRAM
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(PARI) pip(n) = { for(x=1, n, flag=1; y=prime(prime(x)); y2=y; for(j=1, length(Str(y)), r = y%10; if(!isprime(r), flag=0); y = floor(y/10); ); if(flag, print1(y2", ")); ) }
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CROSSREFS
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Sequence in context: A087367 A058846 A101331 this_sequence A087670 A138584 A002427
Adjacent sequences: A087365 A087366 A087367 this_sequence A087369 A087370 A087371
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KEYWORD
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easy,nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), Oct 21 2003
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