%I A097605
%S A097605 1,2,3,5,7,11,13,15,17,19,23,29,31,35,37,41,43,47,53,59,61,65,67,71,73,
%T A097605 79,83,89,91,97,101,103,107,109,113,127,131,137,139,149,151,157,163,167,
%U A097605 173,179,181,191,193,197,199,211,223,227,229,233,239,241,251,255,257
%N A097605 Numbers n such that phi(n) divides n^2 - 1, where phi(n) (A000010) is 
               number of positive integers <= n and coprime to n.
%C A097605 All primes are in the sequence. 2 is the only even integer in the sequence.
%H A097605 Leroy Quet, <a href="http://www.prism-of-spirals.net/">Home Page</a> 
               (listed in lieu of email address)
%e A097605 phi(35) = 24, 24 divides 35^2 -1 = 1224.
%t A097605 Select[ Range[ 262], Mod[ #^2 - 1, EulerPhi[ # ]] == 0 &] (from Robert 
               G. Wilson v Sep 01 2004)
%Y A097605 Cf. A098271, A000010.
%Y A097605 Sequence in context: A003277 A117287 A121615 this_sequence A143578 A086070 
               A117093
%Y A097605 Adjacent sequences: A097602 A097603 A097604 this_sequence A097606 A097607 
               A097608
%K A097605 nonn
%O A097605 1,2
%A A097605 Leroy Quet Aug 30 2004
%E A097605 More terms from Robert G. Wilson v (rgwv(AT)rgwv.com) and John W. Layman 
               (layman(AT)math.vt.edu), Sep 01 2004