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Search: id:A113933
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| A113933 |
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(F5,F7,F8,F9,F10,F11,F12,F14) - 10^n = prime where F stands for the Fermat numbers 2^2^x + 1 where x corresponds to 5,7,8,9,10,11,12 and 14. |
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1
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OFFSET
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2,1
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COMMENT
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This sequence shows that the difference between a composite number and a prime rests on the modification of a single decimal digit. Note that F6 and F13 regarding the Fermat numbers are exceptions to this rule.
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EXAMPLE
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F5 - 10^2 = 4294967197 = prime
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MATHEMATICA
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Position[PrimeQ[Table[2^2^5 + 1 - 10^n, {n, 10}]], True]
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CROSSREFS
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Sequence in context: A067566 A067555 A108705 this_sequence A127871 A109210 A056707
Adjacent sequences: A113930 A113931 A113932 this_sequence A113934 A113935 A113936
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KEYWORD
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nonn
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AUTHOR
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Joao Carlos Leandro da Silva (zxawyh66(AT)yahoo.com), Jan 30 2006
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