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 A048731 #8 Oct 26 2022 16:00:30 %S A048731 1,1,4,15,256,1285,5440,28123,16777216,150994953,1140868096, %T A048731 12465661415,73299656704,952678341901,5584872095744,56294136361779, %U A048731 18446744073709551616,313594649253062377489,4796153459164500459520,91477403861525991461727,1213648186380073308258304 %N A048731 Main diagonal of A048723, a(n) = Xpower(n,n). %H A048731 Alois P. Heinz, <a href="/A048731/b048731.txt">Table of n, a(n) for n = 0..415</a> %Y A048731 Cf. A048723. %K A048731 nonn %O A048731 0,3 %A A048731 _Antti Karttunen_, Apr 26 1999