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Search: id:A155775
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| A155775 |
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Indices j in A000040 such that j is an odd composite and the distinct digits of the prime A000040(j) are in increasing order. |
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+0
1
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| 9, 15, 33, 35, 39, 55, 57, 69, 75, 77, 91, 203, 205, 207, 209, 219, 237, 247, 249, 355, 365, 391, 405, 483, 633, 749, 1475, 1501, 1515, 1595, 1605, 1615, 1631, 2611, 2637, 2829, 11603, 11803, 13479, 20797, 20891, 95375
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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These are the odd composites n (A071904) such that the digits of prime(n) are strictly increasing. The latter defines a subsequence of A028864, which lists primes with non-decreasing digits. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 30 2009]
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EXAMPLE
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If odd number=n=9 and prime(9)=23, then 2<3 and 9=a(1). If odd number=n=15 and prime(15)=47, then 4<7 and 15=a(2). If odd number=n=33 and prime(33)=137, then 1<3<7 and 33=a(3), etc.
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CROSSREFS
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Cf. A000040, A002808, A155079.
Sequence in context: A108637 A091296 A107076 this_sequence A111148 A125216 A058505
Adjacent sequences: A155772 A155773 A155774 this_sequence A155776 A155777 A155778
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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 27 2009
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EXTENSIONS
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Corrected and extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 30 2009
Better definition from Omar E. Pol (info(AT)polprimos.com), Jan 31 2009
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