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 A120264 #11 Feb 16 2025 08:33:01
%S A120264 1,3,85,5413,16922537,456895999,376274084904457,24659496552164597077,
%T A120264 13105067550356276873597957,40953336089635928267832533257,
%U A120264 11684464736880059106484670339210887010027
%N A120264 Numerator of Sum_{k=1..n} (-1)^(k+1)/k^k.
%C A120264 Denominator of Sum_{k=1..n} (1/k^k)*(-1)^(k+1) is A061464(n).
%C A120264 Sum_{k>=1} (-1)^(k+1)/k^k = Integral_{x=0..1} x^x dx = 0.7834305107121344... A083648(n) gives its decimal expansion {7, 8, 3, 4, 3, 0, 5, 1, 0, 7, 1, 2, 1, 3, 4, 4, 0, 7, 0, 5, 9, ...}. - _Alexander Adamchuk_, Aug 21 2006
%H A120264 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SophomoresDream.html">Sophomore's Dream</a>.
%F A120264 a(n) = numerator(Sum_{k=1..n} (1/k^k)*(-1)^(k+1)).
%t A120264 Numerator[Table[Sum[1/k^k*(-1)^(k+1),{k,1,n}],{n,1,20}]]
%Y A120264 Cf. A061463, A061464.
%Y A120264 Cf. A083648.
%K A120264 frac,nonn
%O A120264 1,2
%A A120264 _Alexander Adamchuk_, Jun 30 2006