cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A332021 Elements of the set {m > 0: m is a quadratic nonresidue modulo prime(m)}.

Original entry on oeis.org

2, 3, 6, 7, 8, 10, 11, 13, 15, 18, 21, 24, 26, 27, 28, 32, 33, 39, 41, 44, 45, 48, 50, 52, 54, 55, 56, 58, 60, 62, 65, 68, 69, 71, 74, 75, 79, 83, 84, 85, 88, 90, 93, 95, 101, 107, 108, 109, 110, 114, 116, 117, 118, 119, 120, 122, 123, 124, 126, 129, 130, 131, 133, 135, 139
Offset: 1

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Author

Zhi-Wei Sun, Feb 04 2020

Keywords

Comments

This is the complement sequence of A332020.
The conjecture in A332020 implies that the number of terms not exceeding x is about x/2 asymptotically.

Examples

			a(1) = 2 since 2 is a quadratic nonresidue modulo prime(2) = 3.
a(2) = 3 since 3 is a quadratic nonresidue modulo prime(3) = 5.
		

Crossrefs

Programs

  • Mathematica
    tab = {}; Do[If[JacobiSymbol[n, Prime[n]] == -1, tab = Append[tab, n]], {n, 140}]; tab
  • PARI
    isok(m) = kronecker(m, prime(m)) !=1; \\ Michel Marcus, Feb 06 2020
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