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 A352397 #14 May 16 2022 04:58:09
%S A352397 1,8,41,856,23147,254512,3309041,29780368,168757087,28857376792,
%T A352397 259716622073,5973480691064,89602217802389,7257779456082784,
%U A352397 210475605899597261,6524743766713282016,19574231315333822573,6524743770186190936,2172739675639135323463,19554657080276529569192
%N A352397 Numerators of partial sums of the Madhava series for Pi/(2*sqrt(3)) = A093766.
%C A352397 This Madhava series results from the arctan series for tan(Pi/6) = sqrt(3)/3 = A020760.
%D A352397 L. B. W. Jolley, Summation of Series, Dover (1961), eq. (273), pp. 16 and 17.
%D A352397 Ian Stewart, Grössen der Mathematik, Rowohlt Tachenbuch Verlag, Nr. 63394, 2020, p. 74. [English Original: Significant Figures. Lives and Works of Traiblazing Mathematicians, Profile Books, London, 2017]
%F A352397 a(n) = numerator(Sum_{j=0..n} (-1)^j/((2*j+1)*3^j)), for n >= 0.
%e A352397 The partial sums begin: 1/1, 8/9, 41/45, 856/945, 23147/25515, 254512/280665, 3309041/3648645, 29780368/32837805, 168757087/186080895, ...
%e A352397 For n = 100 the partial sum is 0.9068996821171089252970391288210778661420331240463726... compared to 0.9068996821171089252970391288210778661420331240463702...(the first 53 digits coincide).
%t A352397 Numerator @ Accumulate @ Table[(-1)^j/((2*j + 1)*3^j), {j, 0, 20}] (* _Amiram Eldar_, Apr 08 2022 *)
%o A352397 (PARI) a(n) = numerator(sum(j=0, n, (-1)^j/((2*j+1)*3^j))); \\ _Michel Marcus_, Apr 08 2022
%Y A352397 Cf. A352398 (denominators).
%Y A352397 Cf. A020760, A093766.
%K A352397 nonn,frac,easy
%O A352397 0,2
%A A352397 _Wolfdieter Lang_, Apr 07 2022