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A105437
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Smallest prime which stays prime when a string of n 1's is prepended to it.
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1
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2, 3, 3, 7, 3, 83, 31, 7, 3, 29, 3, 53, 23, 439, 23, 53, 31, 71, 31, 79, 89, 233, 7, 3, 227, 487, 281, 31, 7, 227, 47, 439, 29, 47, 349, 491, 43, 31, 23, 7, 919, 701, 229, 283, 281, 59, 223, 2693, 53, 67, 239, 2011, 2113, 467, 41, 601, 587, 311, 337, 2879, 59, 619, 71
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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EXAMPLE
| a(3)=7 because it is the first prime before 31,59,61,71,73,97,... all remaining prime when 111 is prepended to each of them.
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MATHEMATICA
| f[n_] := Block[{k = 1, t = Table[1, {n}]}, While[id = IntegerDigits[ Prime[k]]; id[[1]] == 1 || !PrimeQ[ FromDigits[ Join[t, id]]], k++ ]; Prime[k]]; Table[ f[n], {n, 0, 62}] (from Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 09 2005)
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CROSSREFS
| Cf. A105436, A065584.
Sequence in context: A082910 A023646 A056225 * A168140 A088100 A097359
Adjacent sequences: A105434 A105435 A105436 * A105438 A105439 A105440
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KEYWORD
| nonn,base
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AUTHOR
| Lekraj Beedassy (blekraj(AT)yahoo.com), Apr 08 2005
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EXTENSIONS
| More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 09 2005
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