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Search: id:A161401
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| A161401 |
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Numbers n such that the count of primes among the permutations of the digits of n is greater than 1. |
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+0
4
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| 13, 17, 31, 37, 71, 73, 79, 97, 101, 103, 104, 106, 107, 109, 110, 113, 118, 119, 124, 125, 127, 128, 130, 131, 133, 136, 137, 139, 140, 142, 146, 149, 152, 157, 160, 163, 164, 167, 169, 170, 172, 173, 175, 176, 179, 181, 182, 190, 191, 193, 194, 196, 197
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Leading zeros in the permutations are ignored.
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LINKS
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Wikipedia,Permutation
C. Hilliard, Comments and PARI program.
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EXAMPLE
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13 has two permutations of its digits 1, 3 that form a prime, namely 13, 31. So the count of primes for 13 is greater than 1 and 13 is in the sequence.
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PROGRAM
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(PARI) Cf. C. Hilliard link.
(MAGMA) [ n: n in [1..200] | #[ s: s in Seqset([ Seqint([m(p[i]):i in [1..#x] ], 10): p in Permutations(Seqset(x)) ]) | IsPrime(s) ] gt 1 where m is map< x->y | [<x[i], y[i]>:i in [1..#x] ] > where x is [1..#y] where y is Intseq(n, 10) ]; [From Klaus Brockhaus, Jun 14 2009]
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CROSSREFS
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Sequence in context: A033210 A107159 A138375 this_sequence A006567 A108388 A083983
Adjacent sequences: A161398 A161399 A161400 this_sequence A161402 A161403 A161404
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KEYWORD
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base,nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)hotmail.com), Jun 09 2009
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EXTENSIONS
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Edited by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jun 14 2009
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