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 A196498 #26 Jul 19 2021 15:00:25
%S A196498 9,9,9,9,9,9,7,2,4,4,2,6,8,0,7,7,6,0,5,5,2,1,2,5,2,3,6,7,5,8,0,2,0,4,
%T A196498 7,6,0,0,1,2,6,3,7,2,0,3,6,6,0,0,3,5,6,2,1,1,9,7,3,3,1,6,3,7,2,8,9,9,
%U A196498 3,3,6,5,8,4,7,2,1,1,6,8,9,6,7,4,0,0,2,7,4,8,2,1,1,9,7,3,8,4,2,5,9,3,0,1,0
%N A196498 Decimal expansion of the constant Sum_{k>=0} (-1)^k/(10*k)!.
%H A196498 Michael I. Shamos, <a href="http://euro.ecom.cmu.edu/people/faculty/mshamos/cat.pdf">A catalog of the real numbers</a> (2011).
%e A196498 0.99999972442680776055212523675802047...
%t A196498 RealDigits[ HypergeometricPFQ[{}, {1/10, 1/5, 3/10, 2/5, 1/2, 3/5, 7/10, 4/5, 9/10}, -10^-10], 10, 105] // First (* _Jean-François Alcover_, Feb 12 2013 *)
%o A196498 (PARI) sumalt(k=0, (-1)^k/(10*k)!) \\ _Michel Marcus_, Jul 18 2021
%Y A196498 Cf. A195070, A195394.
%Y A196498 Cf. A068985, A049470, A346441, A346440, A346439, A346438, A346437, A346436, A346435.
%K A196498 cons,nonn
%O A196498 0,1
%A A196498 _R. J. Mathar_, Oct 03 2011
%E A196498 6 more digits from _Jean-François Alcover_, Feb 12 2013