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Search: id:A111986
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| A111986 |
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Number of numbers having n quadratic residues. |
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+0
3
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| 1, 3, 2, 5, 0, 5, 2, 6, 2, 1, 2, 12, 0, 4, 1, 6, 0, 6, 1, 3, 4, 7, 1, 17, 0, 0, 3, 7, 0, 6, 2, 6, 3, 1, 0, 15, 1, 3, 0, 6, 0, 11, 0, 14, 3, 1, 0, 24, 2, 0, 1, 1, 1, 10, 1, 8, 3, 0, 0, 13, 0, 5, 5, 7, 0, 10, 0, 3, 2, 3, 0, 26, 0, 3, 1, 6, 4, 0, 2, 9, 3, 1, 0, 25, 0, 0, 2, 18, 0, 13, 1, 3, 4, 0, 0, 26
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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a(4)=5 because the numbers 6, 7, 9, 12, and 16 each have 4 quadratic residues.
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MATHEMATICA
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t=Table[Length[Union[Mod[Range[0, n/2]^2, n]]], {n, 10000}]; Table[Length[Position[t, n]], {n, 100}]
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CROSSREFS
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Cf. A037041 (n such that a(n)>0), A037046 (n such that a(n)=0), A111987 (least number having n quadratic residues), A111988 (greatest number having n quadratic residues).
Adjacent sequences: A111983 A111984 A111985 this_sequence A111987 A111988 A111989
Sequence in context: A085015 A083254 A068453 this_sequence A121490 A099643 A113260
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KEYWORD
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nonn
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AUTHOR
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T. D. Noe (noe(AT)sspectra.com), Aug 25 2005
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