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Search: id:A155048
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| A155048 |
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Primes n such that number of prime digits of prime(n) = number of nonprime digits of prime(n). |
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+0
1
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| 7, 11, 19, 23, 191, 199, 211, 227, 251, 277, 281, 311, 337, 347, 353, 359, 373, 383, 389, 397, 401, 409, 419, 439, 463, 467, 523, 547, 557, 569, 571, 577, 593, 599, 613, 619, 641, 643, 653, 659, 673, 677
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Prime digit = 2, 3, 5 or 7. Nonprime digit = 0, 1, 4, 6, 8 or 9.
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EXAMPLE
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If n=7=prime and 17=prime(7), then 1(1)=1(7) and 7=a(1). If n=11=prime and 31=prime(11), then 1(3)=1(1) and 11=a(2). If n=19=prime and 67=prime(19(, then 1(6)=1(7) and 19=a(3). If n=23=prime and 83=prime(23), then 1(8)=1(3) and 23=a(4). If n=191=prime and 1153=prime(191), then 2(1 and 1)=2(5 and 3) and 191=a(4), etc.
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CROSSREFS
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Cf. A000040, A141468.
Sequence in context: A129842 A065312 A141337 this_sequence A053403 A032672 A133425
Adjacent sequences: A155045 A155046 A155047 this_sequence A155049 A155050 A155051
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KEYWORD
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nonn,base
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AUTHOR
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Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Jan 19 2009
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