%I A090083
%S A090083 4,8,28,52,286,364,532,616,946,1036,1288,2806,2926,3052,4376,4636,5356,
%T A090083 6364,8744,8866,11476,12124,15964,17446,19096,19684,21196,21736,24046,
%U A090083 24388,26596,31876
%N A090083 Even pseudoprimes to base 9.
%t A090083 Do[s=Mod[ -1+9^(n-1), n]; If[Equal[s, 0]&&!PrimeQ[n]&&EvenQ[n], Print[n]], 
               {n, 1, 1000000}]
%Y A090083 Cf. A020138.
%Y A090083 Sequence in context: A104042 A117864 A020138 this_sequence A034515 A059480 
               A105723
%Y A090083 Adjacent sequences: A090080 A090081 A090082 this_sequence A090084 A090085 
               A090086
%K A090083 nonn
%O A090083 1,1
%A A090083 Labos E. (labos(AT)ana.sote.hu), Nov 25 2003