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 A305500 #46 Feb 16 2025 08:33:54 %S A305500 0,3375,32768,884736,884736000,147197952000,262537412640768000 %N A305500 a(n) = (-1) * j((1 + sqrt(-A003173(n+2)))/2). %H A305500 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/HeegnerNumber.html">Heegner Number</a> and <a href="https://mathworld.wolfram.com/j-Function.html">j-Function</a> %F A305500 a(n) = A199743(n-1)^3 for n > 1. %e A305500 j((1+sqrt( -3))/2) = 0. %e A305500 j((1+sqrt( -7))/2) = -3375 = (-1) * 15^3. %e A305500 j((1+sqrt( -11))/2) = -32768 = (-1) * 32^3. %e A305500 j((1+sqrt( -19))/2) = -884736 = (-1) * 96^3. %e A305500 j((1+sqrt( -43))/2) = -884736000 = (-1) * 960^3. %e A305500 j((1+sqrt( -67))/2) = -147197952000 = (-1) * 5280^3. %e A305500 j((1+sqrt(-163))/2) = -262537412640768000 = (-1) * 640320^3. %Y A305500 Cf. A003173, A032354, A199743, A305475. %K A305500 nonn,fini,full %O A305500 1,2 %A A305500 _Seiichi Manyama_, Jun 03 2018