A031426 - OEIS

%I #13 Aug 07 2017 09:35:10

%S 2,6,12,20,28,30,41,42,55,56,72,89,90,110,126,130,131,132,155,156,177,

%T 180,182,209,210,240,269,270,272,299,303,305,306,342,368,372,377,380,

%U 418,420,451,458,462,497,504,505,506,552,590,600,646,648

%N Least term in period of continued fraction for sqrt(n) is 2.

%H Charles R Greathouse IV, <a href="/A031426/b031426.txt">Table of n, a(n) for n = 1..10000</a> (first 1000 from Vincenzo Librandi)

%t Select[Range[600], !IntegerQ[Sqrt[#]] && Min[ContinuedFraction[Sqrt[#]][[2]]] == 2&] (* _Vincenzo Librandi_, Feb 06 2012 *)

%K nonn

%O 1,1

%A _David W. Wilson_