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A230375 Squarefree numbers congruent to 2 or 3 mod 4. 7

%I

%S 2,3,6,7,10,11,14,15,19,22,23,26,30,31,34,35,38,39,42,43,46,47,51,55,

%T 58,59,62,66,67,70,71,74,78,79,82,83,86,87,91,94,95,102,103,106,107,

%U 110,111,114,115,118,119,122,123,127,130,131,134,138,139,142,143

%N Squarefree numbers congruent to 2 or 3 mod 4.

%C Also numbers such that the discriminant of the quadratic field Q(sqrt(n)) equals 4n. - _Michel Marcus_, Nov 26 2013

%H Colin Barker, <a href="/A230375/b230375.txt">Table of n, a(n) for n = 1..1000</a>

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Quadratic_field">Quadratic field</a>

%t Select[Range[200],SquareFreeQ[#]&&MemberQ[{2,3},Mod[#,4]]&] (* _Harvey P. Dale_, Feb 04 2015 *)

%o (PARI) s=[]; for(n=1, 200, if(issquarefree(n) && n%4!=1, s=concat(s, n))); s

%Y Cf. A039955, A039957.

%K nonn

%O 1,1

%A _Colin Barker_, Oct 17 2013

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Last modified February 18 21:20 EST 2020. Contains 332028 sequences. (Running on oeis4.)