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Search: id:A095188
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| A095188 |
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Smallest prime formed by the digit string after decimal point of n^(1/2), or 0 if no such prime exists. |
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+0
2
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| 0, 41, 7, 0, 2, 449, 645751, 82842712474619, 0, 162277, 3, 464101615137754587054892683011, 605551, 7, 87298334620741688517926539978239961, 0, 1231, 2, 3, 47, 5
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Conjecture: a(n) is nonzero if n is not a perfect square.
For n=22, no provable primes were found with fewer than 256 digits. - Wouter Meeussen (wouter.meeussen(AT)pandora.be), Jun 04 2004
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EXAMPLE
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a(7) = 645751 as 7^(1/2) = 2.64575131106459059... and the least prime is 645751.
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MATHEMATICA
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<< NumberTheory`PrimeQ`; it = Table[{n, k = 1; While[temp = Floor[10^k FractionalPart[n^(1/2)]]; k < 256 && (temp === 1 || ! ProvablePrimeQ[temp]), k++ ]; temp, k}, {n, 2, 21}]
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CROSSREFS
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Sequence in context: A036189 A106424 A126636 this_sequence A107813 A033361 A077680
Adjacent sequences: A095185 A095186 A095187 this_sequence A095189 A095190 A095191
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KEYWORD
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base,nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Jun 02 2004
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EXTENSIONS
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Corrected and extended by Wouter Meeussen (wouter.meeussen(AT)pandora.be), Jun 04 2004
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