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Search: id:A088465
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| A088465 |
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Primes whose leftmost decimal digit is 1 and whose other decimal digits are all 7s. |
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+0
2
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| 17, 1777, 1777777777, 17777777777777, 1777777777777777777777777777777777777777777, 1777777777777777777777777777777777777777777777777777
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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In no element of this sequence can the number of 7's be congruent to 2 modulo 3
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LINKS
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Vladislav Avrutin, Prime pyramids
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MATHEMATICA
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Do[ a = 10^n + 7(10^n - 1)/9; If[ PrimeQ[a], Print[a]], {n, 1, 53}] (from Robert G. Wilson v Dec 05 2003)
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CROSSREFS
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The number of sevens in this sequence is given by A089147.
Sequence in context: A071826 A055414 A156675 this_sequence A001905 A135505 A092814
Adjacent sequences: A088462 A088463 A088464 this_sequence A088466 A088467 A088468
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KEYWORD
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base,easy,nonn
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AUTHOR
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Sam Alexander (amnalexander(AT)yahoo.com), Nov 12 2003
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