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 A262974 #23 Jul 23 2022 03:18:12
%S A262974 5,9,6,9,6,5,5,5,5,5,7,8,4,8,3,2,2,4,5,7,9,1,2,7,3,6,6,4,9,2,5,6,9,1,
%T A262974 8,3,1,6,4,5,8,8,3,7,5,8,4,1,1,3,6,6,9,6,0,2,1,7,9,9,0,1,2,5,1,6,6,9,
%U A262974 7,8,6,1,3,3,2,4,2,3,4,1,2,7,9,1,0,6,6,0,5,0,2,7,8,6,4,9,3,6,2,5,4,6,8,9,5
%N A262974 Decimal expansion of Sum_{n > 0} (-1/n)^(n-1).
%F A262974 Equals 1 - Integral_{x = 0..1} x^(x+1) dx. - _Peter Bala_, Jul 21 2022
%e A262974 0.5969655555784832245791273664925691831645883...
%p A262974 evalf(Sum((-1/n)^(n-1), n=1..infinity), 120); # _Vaclav Kotesovec_, Oct 15 2015
%t A262974 Sum[(-1/n)^(n-1),{n,1,Infinity}]
%o A262974 (PARI) sumalt(n=1, (-1/n)^(n-1)) \\ _Michel Marcus_, Oct 06 2015
%Y A262974 Cf. A083648, A098686.
%K A262974 nonn,cons
%O A262974 0,1
%A A262974 _Andrew Penton_, Oct 05 2015
%E A262974 More terms from _Michel Marcus_, Oct 15 2015