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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A138326 Numbers not representable as p+g, where p is a prime and g is a primitive root of p.

Original entry on oeis.org

1, 2, 4, 6, 9, 11, 14, 16, 25, 26, 35, 36, 41, 45, 49, 51, 64, 81, 100, 121, 144, 169, 196, 225, 256, 289, 324, 361, 400, 441, 484, 529, 576, 625, 676, 729, 784, 841, 900, 961, 1024, 1089, 1156, 1225, 1296, 1369, 1444, 1521, 1600, 1681, 1764, 1849, 1936, 2025
Offset: 1

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Author

T. D. Noe, Mar 14 2008

Keywords

Comments

This sequence appears to contain all the positive squares (A000290) and a few other numbers (A138327).

Crossrefs

Cf. A000290, A060749 (primitive roots), A138327.

Programs

  • Mathematica
    seq[m_] := Module[{p = Select[Range[m], PrimeQ]}, Complement[Range[m], p + PrimitiveRootList[p] // Flatten]]; seq[2000] (* Amiram Eldar, Oct 09 2021 *)
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