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OFFSET
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1,1
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COMMENTS
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Indices where number 1 occured in A138789.
There are no more primes for n<=5000.
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LINKS
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EXAMPLE
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a(1) = 61 because the number 160695...654321 is prime.
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MATHEMATICA
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b = {}; a = {}; Do[w = RealDigits[n]; w = First[w]; Do[AppendTo[a, w[[k]]], {k, 1, Length[w]}]; p = FromDigits[Reverse[a]]; If[PrimeQ[p], Print[n]; AppendTo[b, p]], {n, 1, 2000}]; b (* Artur Jasinski, Mar 30 2008 *)
Select[Range[1, 1000], PrimeQ[lst = {}; Do[lst = Join[lst, IntegerDigits[n]], {n, 1, #}]; FromDigits[Reverse[lst]]] &] (* Robert Price, Mar 24 2015 *)
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CROSSREFS
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KEYWORD
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nonn,bref,hard,more,base
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AUTHOR
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STATUS
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approved
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