Squarefree-level weight-four Eisenstein congruence conjecture
Let N1N_1N1 and N2N_2N2 be coprime squarefree positive integers, with ω(N1)\omega(N_1)ω(N1) odd, and let E4E_4E4 be the weight-444 Eisenstein series on SL2(Z)\operatorname{SL}_2(\mathbb Z)SL2(Z). Squarefr…