OFFSET
1,1
COMMENTS
If A(x) is the counting function of the terms not exceeding x, then A(x) grows similarly to Pi(x)/3, see A000720.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..2000
FORMULA
{prime(k) : A023506(k) is even}. - R. J. Mathar, May 08 2009
MATHEMATICA
fQ[n_] := Mod[ Flatten[ FactorInteger[n - 1]] [[2]], 2] == 0; Select[ Prime@ Range@ 155, fQ@# &] (* Robert G. Wilson v, May 31 2009 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, May 04 2009
EXTENSIONS
Edited by R. J. Mathar, May 08 2009
More terms from Robert G. Wilson v, May 31 2009
STATUS
approved