A138326 - OEIS

A138326

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

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

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OFFSET

1,2

COMMENTS

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

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..375

MATHEMATICA

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

CROSSREFS

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

Sequence in context: A085223 A163057 A242137 * A274214 A276223 A288468

Adjacent sequences: A138323 A138324 A138325 * A138327 A138328 A138329

KEYWORD

nonn

AUTHOR

T. D. Noe, Mar 14 2008

STATUS

approved