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 A381352 #37 May 14 2025 19:36:51 %S A381352 11,14,15,20,24,27,32,36,48,64,80,144 %N A381352 Conductors admitting a normalized weight-2 eta-quotient newform. %C A381352 By the modularity theorem, each Q-isogeny class of elliptic curves of conductor N corresponds to a unique normalized rational weight-2 newform on Gamma_0(N). This sequence (classified by Martin & Ono) lists exactly those 12 conductors N for which that newform at level N can be written as a single eta-quotient. %H A381352 Yves Martin and Ken Ono, <a href="https://doi.org/10.1090/S0002-9939-97-03928-2">Eta-Quotients and Elliptic Curves</a>, Proc. Amer. Math. Soc. 125, No 11 (1997), 3169-3176. %e A381352 a(1) = 11 since f(z) = q-2*q^2-q^3+2*q^4+ ... = eta^2(z)*eta^2(11*z) on Gamma_0(11) %Y A381352 Cf. A005788, A060564, A110620. %K A381352 nonn,fini,full %O A381352 1,1 %A A381352 _Dimitris Cardaris_, May 11 2025