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 A341558 #13 Mar 31 2023 09:23:37
%S A341558 0,0,1,-12,54,-100,45,-108,692,-108,-2970,1012,4542,13176,-25168,
%T A341558 -33660,27864,97944,61641,-295812,-142780,227172,613548,-32656,
%U A341558 -1181916,54000,449990,1389960,-1340064,-1153484,2112750,18684,1743312,-6661260,733698,2254360,3347622
%N A341558 Fourier coefficients of the modular form (1/t_{3A}^2) * F_{3A}^12.
%H A341558 Masao Koike, <a href="/A004016/a004016.pdf">Modular forms on non-compact arithmetic triangle groups</a>, Unpublished manuscript [Extensively annotated with OEIS A-numbers by N. J. A. Sloane, Feb 14 2021. Sloane wrote 2005 on the first page but the internal evidence suggests 1997.] See page 30.
%F A341558 1/t_{3A} is A030197, F_{3A} is A004016. - _Georg Fischer_, Mar 31 2023
%Y A341558 Cf. A004016, A030197, A136747, A341556, A341557, A341561.
%K A341558 sign
%O A341558 0,4
%A A341558 _Robert C. Lyons_, Feb 14 2021
%E A341558 More terms from _Georg Fischer_, Mar 31 2023