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Search: id:A112386
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| A112386 |
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Smallest prime obtained by appending one or more 1's to n. |
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+0
2
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| 11, 211, 31, 41, 511111, 61, 71, 811, 911, 101, 1111111111111111111, 121111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111, 131, 14111111111, 151, 16111, 1711111111, 181, 191, 2011, 211, 22111, 2311, 241
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Number of appended ones: 1,2,1,1,5,1,1,2,2,1,17,1,1,2,7,1,2,1,1,2,2,67,2,4,217,3,2,1,6,1,.., . - Robert G. Wilson v, Dec 05 2005
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EXAMPLE
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a(5) = 511111 because 51, 511, 5111 and 51111 are not primes.
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MATHEMATICA
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f[n_] := Block[{k = 1, e = Floor[Log[10, n] + 1]}, While[ !PrimeQ[n*10^k + (10^k - 1)/9], k++ ]; n*10^k + (10^k - 1)/9]; Array[f, 24] (* Robert G. Wilson v *)
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CROSSREFS
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Sequence in context: A034909 A081788 A060496 this_sequence A124991 A068836 A069628
Adjacent sequences: A112383 A112384 A112385 this_sequence A112387 A112388 A112389
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KEYWORD
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nonn,base
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AUTHOR
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Michel Dauchez (mdzdm(AT)yahoo.fr), Dec 04 2005
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EXTENSIONS
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Edited, corrected and extended by Robert G. Wilson v (rgwv(at)rgwv.com), Dec 05 2005
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