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Search: id:A088574
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| A088574 |
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Representative dismal primes. |
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+0
1
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| 19, 90, 99, 109, 901, 902, 909, 1009, 1019, 1029, 1091, 1092, 1099, 1109, 1209, 1901, 1902, 1909, 2019, 2091, 2109, 2901, 9001, 9009, 9011, 9012, 9019, 9021, 9091, 9099, 9101, 9102, 9109, 9201, 9901, 9909, 10009, 10019, 10029, 10091, 10092, 10099
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OFFSET
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1,1
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COMMENT
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Let P = ...9..9ij...kl9...9... be a dismal prime (A087097), where the digits ij...kl are a typical string of consecutive digits that are not 9. Any number Q obtained from P by replacing ij...kl by other non-9-ish digits with the same order relationship as ij...kl is also prime. Sequence gives lexicographically earliest member of each such equivalence class.
It is necessary to consider order relations of all non-9 digits, not just consecutive ones. For example, 9091 is prime, but 9491 = 91*949. - David Wasserman (wasserma(AT)spawar.navy.mil), Aug 11 2005
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EXAMPLE
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109, 209, 219, 309, 319, 329, 409, 419, ..., 879 are all dismal primes in the same class, ij9 with i>j, of which 109 is the earliest.
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CROSSREFS
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Cf. A087097.
Sequence in context: A142089 A124947 A126406 this_sequence A096031 A039409 A038653
Adjacent sequences: A088571 A088572 A088573 this_sequence A088575 A088576 A088577
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KEYWORD
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nonn,easy
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AUTHOR
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njas and David Applegate (david(AT)research.att.com), Nov 18 2003
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EXTENSIONS
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More terms from David Wasserman (wasserma(AT)spawar.navy.mil), Aug 11 2005
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