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Search: id:A119680
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| A119680 |
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Primes with zeros inserted between digits that are Then new primes starting at n=5 where there are two digit primes. |
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+0
1
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| 101, 103, 107, 109, 307, 401, 503, 509, 601, 607, 701, 709, 809, 907, 10007, 10009, 10103, 10301, 10501, 10607, 10709, 10903, 10909, 20101, 20507, 20707, 20903, 30103, 30307, 30509, 30703, 30803, 30809, 40009, 40507, 40709, 50707, 50909
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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a(n) = If prime[n] with zeros inserted is prime, then newprime[n]
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EXAMPLE
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11->101
13->103
17->107
19->109
23-> not prime at 203
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MATHEMATICA
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a = Table[Table[Mod[Floor[Prime[m]/10^n], 10], {n, 4, 0, -1}], {m, 5, 200}]; Dimensions[a] b = Table[Sum[(If[Mod[n - 1, 2] == 0, a[[m, 1 + Floor[(n - 1)/2]]], 0])*10^(9 - n), {n, 1, 9}], {m, 1, 195}]; c = Flatten[Table[If[PrimeQ[b[[m]]], b[[m]], {}], {m, 1, 195}]]
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CROSSREFS
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Sequence in context: A085821 A056709 A134809 this_sequence A166571 A117837 A060400
Adjacent sequences: A119677 A119678 A119679 this_sequence A119681 A119682 A119683
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KEYWORD
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nonn,base,uned
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AUTHOR
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Roger Bagula (rlbagulatftn(AT)yahoo.com), Jun 11 2006
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