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 A230375 Squarefree numbers congruent to 2 or 3 mod 4. 7
 2, 3, 6, 7, 10, 11, 14, 15, 19, 22, 23, 26, 30, 31, 34, 35, 38, 39, 42, 43, 46, 47, 51, 55, 58, 59, 62, 66, 67, 70, 71, 74, 78, 79, 82, 83, 86, 87, 91, 94, 95, 102, 103, 106, 107, 110, 111, 114, 115, 118, 119, 122, 123, 127, 130, 131, 134, 138, 139, 142, 143 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Also numbers such that the discriminant of the quadratic field Q(sqrt(n)) equals 4n. - Michel Marcus, Nov 26 2013 The asymptotic density of this sequence is 4/Pi^2 (A185199). - Amiram Eldar, Feb 23 2021 LINKS Colin Barker, Table of n, a(n) for n = 1..1000 Wikipedia, Quadratic field. MATHEMATICA Select[Range[200], SquareFreeQ[#]&&MemberQ[{2, 3}, Mod[#, 4]]&] (* Harvey P. Dale, Feb 04 2015 *) PROG (PARI) s=[]; for(n=1, 200, if(issquarefree(n) && n%4!=1, s=concat(s, n))); s CROSSREFS Cf. A039955, A039957, A185199. Sequence in context: A053438 A042964 A338064 * A062837 A190670 A226115 Adjacent sequences: A230372 A230373 A230374 * A230376 A230377 A230378 KEYWORD nonn AUTHOR Colin Barker, Oct 17 2013 STATUS approved

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Last modified February 2 05:15 EST 2023. Contains 359997 sequences. (Running on oeis4.)