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 A062811 #16 Aug 10 2025 14:22:40
%S A062811 1,1,3,9,21,65,215,713,2809,11425,49339,234825,1148013,6009153,
%T A062811 33216239,190115849,1152491825,7244099617,47387741107,323632894729,
%U A062811 2280785100549,16702573959489,126413562204231,986688266888777
%N A062811 a(n) = Sum_{i=1..n} i^(n - i) + (i - n)^i.
%H A062811 Seiichi Manyama, <a href="/A062811/b062811.txt">Table of n, a(n) for n = 1..600</a>
%e A062811 a(3) = 1^2 + (-2)^1 + 2^1 + (-1)^2 + 3^0 + 0^3 = 3.
%t A062811 Table[Sum[i^(n-i)+(-1)^i*(n-i)^i,{i,1,n}],{n,25}] (* _Harvey P. Dale_, Aug 10 2025 *)
%o A062811 (PARI) a(n) = sum(i=1, n, i^(n-i) + (i-n)^i); \\ _Michel Marcus_, Mar 24 2019
%Y A062811 Cf. A062810, A062812.
%K A062811 nonn,easy
%O A062811 1,3
%A A062811 _Olivier Gérard_, Jun 23 2001
%E A062811 Previous Mathematica program replaced by _Harvey P. Dale_, Aug 10 2025