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 A251809 #37 Dec 17 2024 10:25:21
%S A251809 1,0,2,7,7,2,2,5,8,5,9,3,6,8,5,8,5,6,7,8,7,9,2,5,6,6,1,8,0,0,2,2,5,5,
%T A251809 7,6,7,2,1,0,1,0,0,3,1,8,5,3,6,9,9,7,4,6,5,3,3,1,0,8,4,7,5,5,1,8,5,2,
%U A251809 5,7,7,7,2,4,6,8,5,8,4,9,6,8,0,3,5,1
%N A251809 Decimal expansion of 3*sqrt(2)*Pi^3/128.
%C A251809 Equals the value of the Dirichlet L-series of the non-principal character modulo 8 (A188510) at s=3. - _Jianing Song_, Nov 16 2019
%D A251809 L. B. W. Jolley, Summation of series, Dover Publications Inc. (New York), 1961, p. 64 (formula 340).
%H A251809 G. C. Greubel, <a href="/A251809/b251809.txt">Table of n, a(n) for n = 1..10000</a>
%H A251809 R. J. Mathar, <a href="https://arxiv.org/abs/1008.2547">Table of Dirichlet L-series and prime zeta modulo functions for small moduli</a>, Section 2.2 L(m=8, r=4, s=3).
%H A251809 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%F A251809 Equals Sum_{i >= 0} (-1)^floor(i/2)/(2i+1)^3 = +1 +1/3^3 -1/5^3 -1/7^3 +1/9^3 +1/11^3 - ...
%F A251809 Equals Sum_{i >= 1} A188510(i)/i^3 = Sum_{i >= 1} Kronecker(-8,i)/i^3. - _Jianing Song_, Nov 16 2019
%F A251809 Equals 1/(Product_{p prime == 1 or 3 (mod 8)} (1 - 1/p^3) * Product_{p prime == 5 or 7 (mod 8)} (1 + 1/p^3)). - _Amiram Eldar_, Dec 17 2023
%e A251809 1.027722585936858567879256618002255767210100318536997465331084755185...
%t A251809 RealDigits[3 Sqrt[2] Pi^3/128, 10, 90][[1]]
%o A251809 (PARI) 3*sqrt(2)*Pi^3/128 \\ _G. C. Greubel_, Jul 27 2018
%o A251809 (Magma) R:= RealField(); 3*Sqrt(2)*Pi(R)^3/128; // _G. C. Greubel_, Jul 27 2018
%Y A251809 Cf. A153071: Sum_{i >= 0} (-1)^i/(2i+1)^3.
%Y A251809 Cf. A233091: Sum_{i >= 0} 1/(2i+1)^3.
%Y A251809 Cf. A093954, A188510.
%K A251809 nonn,cons
%O A251809 1,3
%A A251809 _Bruno Berselli_, Dec 10 2014