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A028732
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Nonsquares mod 19.
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1
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OFFSET
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1,1
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LINKS
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EXAMPLE
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Since 10 is not a perfect square, and there are no solutions in integers to x^2 = 10 mod 19, 10 is in the sequence.
Although 11 is not a perfect square either, there are solutions in integers to x^2 = 11 mod 19, such as x = 7, x = 12. Hence 11 is not in the sequence.
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MATHEMATICA
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Select[Range[18], JacobiSymbol[#, 19] != 1 &] (* Alonso del Arte, Nov 19 2019 *)
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PROG
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(Scala) val squaresMod19 = (0 to 18).map(n => n * n).map(_ % 19)
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CROSSREFS
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KEYWORD
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nonn,fini,full
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AUTHOR
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STATUS
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approved
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