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 A276023 #15 Feb 16 2025 08:33:36 %S A276023 3,2,9,8,5,0,8,9,0,2,7,3,8,7,0,6,8,6,9,3,8,2,1,0,6,5,0,3,7,4,4,5,1,1, %T A276023 7,0,3,6,9,4,4,7,9,0,9,1,5,6,1,8,3,4,3,8,5,3,1,9,5,4,6,5,6,1,3,5,3,5, %U A276023 1,0,4,4,9,3,3,1,7,1,4,5,7,9,9,8,2,9,6,2,7,0,0,0,1,2,7,9,9,7,4,7,7,5,7,6,8,6,2,9,0,0,0,5,4,6,3,5,9,5,9,3 %N A276023 Decimal expansion of 32*Pi^4/945. %C A276023 Volume of the 9-dimensional unit sphere. %C A276023 More generally, the ordinary generation function for the volume of the n-dimensional unit sphere is exp(Pi*x^2)*(erf(sqrt(Pi)*x) + 1) = 1 + 2*x + Pi*x^2 + (4*Pi/3)*x^3 + (Pi^2/2)*x^4 + ... %H A276023 G. C. Greubel, <a href="/A276023/b276023.txt">Table of n, a(n) for n = 1..10000</a> %H A276023 Ilya Gutkovskiy, <a href="/A276023/a276023.pdf">Volume of the n-dimensional unit sphere</a> %H A276023 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Hypersphere.html">Hypersphere</a> %H A276023 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a> %F A276023 Equals 32*A092425*A021949. %e A276023 3.2985089027387068693821065037445117... %t A276023 RealDigits[(32 Pi^4)/945, 10, 120][[1]] %o A276023 (PARI) (32*Pi^4)/945 \\ _G. C. Greubel_, Apr 09 2017 %Y A276023 Cf. A021949, A092425. %Y A276023 Cf. similar sequences of the volume of the n-dimensional unit sphere: A000796 (n = 2), 10*A019699 (n = 3), A102753 (n = 4), A164103 (n = 5), A164105 (n = 6), A164106 (n = 7), A164108 (n = 8). %K A276023 nonn,cons %O A276023 1,1 %A A276023 _Ilya Gutkovskiy_, Aug 16 2016