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A114783
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Smallest prime of the form: all ones followed by prime(n). a(n) >prime(n). 0 if no such prime exists.
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4
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0, 13, 0, 17, 1111111111111111111, 113, 1117, 11119, 1123, 1129, 131, 137, 11111141, 111143, 11111111111111111111111111111147, 1153, 11159, 11161, 167, 1171, 173, 179, 1111183, 1111189, 197, 11111101, 1103, 11111111111111107, 1109
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OFFSET
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1,2
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COMMENTS
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Prime(n) is all zeros followed by prime(n). This is all ones followed by prime(n). Conjecture: No term is zero except a(1) = a(3) = 0.
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LINKS
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EXAMPLE
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a(7) = 1117, as 117 is composite prime(8) = 17.
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MATHEMATICA
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spf[n_]:=Module[{x=IntegerLength[n]+1, idn=IntegerDigits[n]}, While[ !PrimeQ[ FromDigits[ PadLeft[ idn, x, 1]]], x++]; FromDigits[ PadLeft[ idn, x, 1]]]; Join[{0, 13, 0}, spf/@Prime[Range[4, 30]]] (* Harvey P. Dale, May 22 2014 *)
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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