%I A083733
%S A083733 561,1105,2465,3277,8321,10585,18721,29341,46657,62745,75361,104653,
%T A083733 115921,162401,219781,226801,252601,278545,294409,314821,334153,340561,
%U A083733 399001,410041,449065,488881,512461,530881,534061,552721,574561,587861
%N A083733 Pseudoprimes to bases 2 and 7.
%H A083733 R. J. Mathar, <a href="b083733.txt">Table of n, a(n) for n=1..138</a>
%H A083733 F. Richman, <a href="http://www.math.fau.edu/Richman/carm.htm">Primality 
               testing with Fermat's little theorem</a>
%F A083733 a(n) = n-th positive integer k(>1) such that 2^(k-1) = 1 (mod k) and 
               7^(k-1) = 1 (mod k)
%e A083733 a(1)=561 since it is the first positive integer k(>1) which satisfies 
               2^(k-1) = 1 (mod k) and 7^(k-1) = 1 (mod k)
%o A083733 Assembly
%Y A083733 Sequence in context: A104016 A002997 A087788 this_sequence A048123 A131672 
               A083732
%Y A083733 Adjacent sequences: A083730 A083731 A083732 this_sequence A083734 A083735 
               A083736
%K A083733 easy,nonn
%O A083733 1,1
%A A083733 Serhat Sevki Dincer (sevki(AT)ug.bilkent.edu.tr), May 05 2003