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1,2
Includes 341 which is first pseudoprime to base 2 and distinguishes sequence from A008578.
First composite even term is a(14868) = 161038 = A006935(2). - Max Alekseyev, Feb 11 2015
If n is a term, then so is 2^n - 1. - Max Alekseyev, Sep 22 2016
Alois P. Heinz, Table of n, a(n) for n = 1..20000
A015919 = {1} U A000040 U A001567 U A006935 = A001567 U A006935 U A008578. - Ray Chandler, Dec 07 2003; corrected by Max Alekseyev, Feb 11 2015
Prepend[Select[Range[1000], Mod[2^#, #] == 2 &], 1] (* Geoffrey Critzer, Apr 29 2015 *)
(PARI) is(n)=Mod(2, n)^n==2 \\ Charles R Greathouse IV, Mar 11 2014
Contains A002997 as a subsequence.
The odd terms form A176997.
Cf. A000040, A001567, A008578.
Sequence in context: A216886 A273960 A100726 * A064555 A216887 A095320
Adjacent sequences: A015916 A015917 A015918 * A015920 A015921 A015922
nonn
Robert G. Wilson v
approved