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 A253299 #13 May 22 2024 11:25:09
%S A253299 8,9,6,4,8,8,7,8,1,9,2,9,6,2,3,3,4,1,3,0,0,2,3,8,5,2,0,7,9,2,5,5,0,3,
%T A253299 6,5,9,1,8,6,2,5,0,4,6,1,9,5,3,8,1,0,3,6,6,5,6,1,9,3,9,7,2,8,7,3,5,9,
%U A253299 5,8,8,9,0,8,1,9,1,5,8,0,4,5,9,6,7,5,4,8,3,0,7,1,7,0,1,5,3,6,6,0,8,6,6
%N A253299 Decimal expansion of integral_{x=0..1} x^(x^2) dx.
%D A253299 Paul J. Nahin, Inside Interesting Integrals, Springer 2014, ISBN 978-1493912766.
%H A253299 Paul J. Nahin, <a href="https://doi.org/10.1007/978-3-030-43788-6">Inside interesting integrals</a>, Undergrad. Lecture Notes in Physics, Springer (2020), (6.1.5)
%F A253299 Equals sum_{n >= 0} (-1)^n/(2n + 1)^(n + 1).
%e A253299 0.896488781929623341300238520792550365918625...
%t A253299 NIntegrate[x^(x^2), {x, 0, 1}, WorkingPrecision -> 103] // RealDigits // First
%o A253299 (PARI) intnum(x=0,1, x^(x^2)) \\ _Michel Marcus_, Dec 30 2014
%Y A253299 Cf. A073009, A083648, A253300.
%K A253299 nonn,cons,easy
%O A253299 0,1
%A A253299 _Jean-François Alcover_, Dec 30 2014