%I A065005
%S A065005 2,6,12,19,20,29,30,41,42,54,55,56,70,71,72,88,89,90,107,108,109,110,
%T A065005 129,130,131,132,153,154,155,156,178,179,180,181,182,206,207,208,209,
%U A065005 210,236,237,238,239,240,267,268,269,270,271,272,301,302,303,304,305
%N A065005 Integers for which the periodic part of the continued fraction for the 
               square root of n begins with 2.
%e A065005 The continued fraction for the square root of 12 is 3, {2, 6}.
%t A065005 Select[ Range[500], First[ Last[ ContinuedFraction[ Sqrt[ # ]]]] == 2 
               & ]
%Y A065005 Sequence in context: A125024 A053660 A104969 this_sequence A139084 A086958 
               A130492
%Y A065005 Adjacent sequences: A065002 A065003 A065004 this_sequence A065006 A065007 
               A065008
%K A065005 easy,nonn
%O A065005 1,1
%A A065005 Robert G. Wilson v (rgwv(AT)rgwv.com), Nov 01 2001