This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A076352 #10 Feb 24 2024 11:04:45 %S A076352 1,2,15,30,143,286,2145,3599,4290,5183,7198,10366,11663,23326,32399, %T A076352 36863,51983,53985,57599,64798,73726,77745,97343,103966,107970,115198, %U A076352 121103,155490,174945,176399,186623,194686,242206,349890,352798,359999,373246,435599,485985 %N A076352 Squarefree numbers k such that A076341(k) = 0. %e A076352 Applying the map as defined in A076340, A076341: %e A076352 A005117(19) = 30 = 5*3*2 = (4+1)*(4-1)*2 -> (4,1)*(4,-1)*(2,0) = (4*4+1,4-4)*(2,0) = (34,0), therefore A076340(30) = 34 and A076341(30) = 0, hence 30 is a term. %e A076352 A005117(28) = 42 = 7*3*2 = (8-1)*(4-1)*2 -> (8,-1)*(4,-1)*(2,0) = (8*4-1,-8-4)*(2,0) = (62,-24), therefore A076340(42) = 62 and A076341(42) = -24, hence 42 is not a term. %t A076352 f[p_, e_] := 4*(Floor[p/4] + Floor[Mod[p, 4]/2]) + (2 - Mod[p, 4])*I; f[2, e_] := 2; s[1] = 1; s[n_] := Times @@ f @@@ FactorInteger[n]; Select[Range[500000], SquareFreeQ[#] && Im[s[#]] == 0 &] (* _Amiram Eldar_, Feb 24 2024 *) %Y A076352 Cf. A005117, A076340, A076341, A076348. %K A076352 nonn %O A076352 1,2 %A A076352 _Reinhard Zumkeller_, Oct 08 2002 %E A076352 More terms from _Amiram Eldar_, Feb 24 2024