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 A221208 #39 Feb 16 2025 08:33:18
%S A221208 1,5,7,0,7,9,6,3,2,6,7,7,1,7,9,6,0,4,6,5,0,5,8,4,0,8,9,4,2,4,6,4,9,5,
%T A221208 8,5,4,7,5,0,6,5,9,3,1,8,3,8,7,5,3,2,5,9,5,9,8,0,2,2,7,5,8,2,3,5,4,7,
%U A221208 7,6,9,6,2,7,6,6,9,2,6,3,9,1,0,7,0,4,9,6,6,6,1,7,9,3,8,6,3,4,7,3,4,0,5,0,3
%N A221208 Decimal expansion of the Borwein integral with 8 sinc functions.
%C A221208 The difference from Pi/2 (A019669) is approximately 0.231006*10^(-10).
%H A221208 Alois P. Heinz, <a href="/A221208/b221208.txt">Table of n, a(n) for n = 1..10000</a>
%H A221208 Eric Weisstein's MathWorld, <a href="https://mathworld.wolfram.com/BorweinIntegrals.html">Borwein Integrals</a>
%H A221208 Wikipedia, <a href="http://en.wikipedia.org/wiki/Borwein_integral">Borwein integral</a>
%F A221208 Equals 467807924713440738696537864469/935615849440640907310521750000*Pi. - _Alois P. Heinz_, Feb 28 2020
%F A221208 Equals Pi/2*A068214(7)/A144616(7). - _Andrey Zabolotskiy_, Jan 04 2023
%e A221208 1.57079632677179604650584089424649585475065931838753259598...
%t A221208 Integrate[Product[Sinc[x/(2*k+1)], {k, 0, 7}], {x, 0, Infinity}] // RealDigits[#, 10, 105]& // First
%Y A221208 Cf. A000796, A019669, A068214, A068215, A144616, A091473.
%K A221208 cons,nonn,easy
%O A221208 1,2
%A A221208 _Jean-François Alcover_, Feb 21 2013