A206023 - OEIS

A206023

2^n == 3n+2 (mod n^2-2n).

3, 5, 7, 13, 19, 31, 43, 61, 73, 103, 109, 139, 151, 181, 193, 199, 229, 241, 271, 283, 313, 349, 421, 433, 463, 523, 563, 571, 601, 619, 643, 645, 647, 661, 811, 823, 829, 859, 883, 1021, 1033, 1051, 1063, 1093, 1105, 1153, 1231, 1279, 1291, 1303, 1321, 1429

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Consists of n such that each of n and n-2 are either prime (A000040) or Sarrus pseudoprimes (A001567).

Includes the upper twin primes (A006512).

LINKS

David W. Wilson, Table of n, a(n) for n = 1..10000

MATHEMATICA

Join[{3, 5}, Select[Range[6, 1500], PowerMod[2, #, #^2-2#]==3#+2&]] (* Harvey P. Dale, Oct 21 2024 *)

CROSSREFS

Cf. A000040, A001567, A006512.