%I A054395
%S A054395 4,6,9,10,14,21,22,25,26,34,38,39,45,46,49,55,57,58,62,74,82,86,93,94,
%T A054395 99,105,106,111,118,121,122,129,134,142,146,153,155,158,165,166,169,
%U A054395 175,178,183,194,195,201,202,203,205,206,207,214,218,219,226,231,237
%N A054395 Numbers n such that there are precisely 2 groups of order n.
%H A054395 H.-U. Besche, <a href="http://www-public.tu-bs.de:8080/~hubesche/small.html">
               The Small Groups library</a>
%H A054395 Gordon Royle, <a href="http://www.cs.uwa.edu.au/~gordon/remote/cubcay/
               index.html">Numbers of Small Groups</a>
%F A054395 Numbers of the form p^2 and p_1*p_2*...*p_k where for exactly one pair 
               (i, j) p_i | p_j - 1.
%Y A054395 Cf. A000001, A003277, A054395, A054396, A054397, A055561, A135850.
%Y A054395 Sequence in context: A078972 A115652 A084759 this_sequence A142863 A132435 
               A108631
%Y A054395 Adjacent sequences: A054392 A054393 A054394 this_sequence A054396 A054397 
               A054398
%K A054395 nonn
%O A054395 1,1
%A A054395 N. J. A. Sloane (njas(AT)research.att.com), May 21 2000
%E A054395 More terms, formula from Christian G. Bower (bowerc(AT)usa.net), May 
               25 2000