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 A241098 #18 Apr 27 2014 07:11:37 %S A241098 1,3,225,250047,4228250625,1120413075641343,4715453174592516890625, %T A241098 316777275155162685106909462527, %U A241098 340240830764391036687105719527812890625,5845805845679338940092384222659294205213252255743,1606922719369349023077959288770050490334792256259918212890625 %N A241098 (4^n - 1)^n. %F A241098 (4^n - 1)^n %e A241098 a(3) = 63^3 = 250047. %o A241098 (PARI) a(n) = (4^n - 1)^n; \\ _Michel Marcus_, Apr 16 2014 %Y A241098 Cf. A055601, A060613, A241095, A240091. %K A241098 nonn %O A241098 0,2 %A A241098 _Hannah Ko_, Apr 15 2014