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A090869
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Irregular primes whose indices are irregular primes of order one.
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0
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613, 877, 1117, 1721, 1753, 2153, 2557, 2671, 4349, 4943, 5039, 5179, 5443, 5641, 5939, 6037, 6827, 6997, 7591, 7853, 8069, 8209, 8527, 8669, 9221, 9311, 9377, 9859, 10729, 11149, 11353, 11503, 11933, 12211, 12413, 12743, 12923, 13001, 13037
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| The number of primes in this sequence is infinite.
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LINKS
| M. A. Shokrollahi, Tables
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EXAMPLE
| 37 is the first irregular prime, 613 is the 37-th irregular prime, i.e. iprime[iprime[1]] = 613, so 613 is a member.
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PROG
| (PARI) \ Irregular prime index primes. Download the ir12mill2.txt file from this link into the gp working dir http://groups.yahoo.com/group/B2LCC/files/Bernoulli/ This was simplified from Shokrollahi's table. ftp://ftp.reed.edu/pub/users/jpb/ Start a new PARI session. Default(histsize, 310443). Perform irp12mill2.txt to read in the file.
iprimetable(n) = \ run this only once to produce the iprime[] array { iprime = vector(310443); for (i = 1, n, iprime[i] = eval( Str("%", i)); ) }
ipips(n) = { for(x=1, n, y=iprime[iprime[x]]; \ ipips of order 1 print1(y", ")) }
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CROSSREFS
| Sequence in context: A159641 A100364 A142435 * A020372 A032657 A117503
Adjacent sequences: A090866 A090867 A090868 * A090870 A090871 A090872
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KEYWORD
| easy,nonn
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AUTHOR
| Cino Hilliard (hillcino368(AT)gmail.com), Feb 12 2004
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