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Search: id:A066755
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| A066755 |
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Numbers n such that n^2+1 is not divisible by k^2+1 for any k in [1,n-1]. |
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+0
1
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| 1, 2, 4, 6, 10, 14, 16, 20, 24, 26, 34, 36, 40, 44, 46, 50, 54, 56, 60, 66, 70, 74, 76, 84, 86, 90, 94, 96, 100, 104, 110, 114, 116, 120, 124, 126, 130, 134, 136, 144, 146, 150, 156, 160, 164, 170, 176, 180, 184, 186, 190, 194, 196, 204, 206, 210, 214, 220, 224
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OFFSET
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1,2
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COMMENT
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Equivalently, A066743(n)=1.
If n^2+1 is prime, n is in the sequence; i.e. the sequence contains A005574. But so are many other values of n: 34,44,46,50,60,70,76,86,96,...
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MATHEMATICA
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a66743[ n_ ] := Length[ Select[ Range[ 1, n ], IntegerQ[ (n^2+1)/(#^2+1) ]& ] ]; Select[ Range[ 1, 300 ], a66743[ # ]==1& ]
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CROSSREFS
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Cf. A066743, A005574.
Sequence in context: A007981 A075574 A104692 this_sequence A089238 A005574 A109807
Adjacent sequences: A066752 A066753 A066754 this_sequence A066756 A066757 A066758
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KEYWORD
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nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Jan 16 2002
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EXTENSIONS
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Edited by Dean Hickerson (dean(AT)math.ucdavis.edu), Jan 20 2002
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