A221208 Decimal expansion of the Borwein integral with 8 sinc functions.

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, 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, 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

Offset

1,2

Comments

The difference from Pi/2 (A019669) is approximately 0.231006*10^(-10).

Links

Alois P. Heinz, Table of n, a(n) for n = 1..10000

Eric Weisstein's MathWorld, Borwein Integrals

Wikipedia, Borwein integral

Formula

Equals 467807924713440738696537864469/935615849440640907310521750000*Pi. - Alois P. Heinz, Feb 28 2020

Equals Pi/2*A068214(7)/A144616(7). - Andrey Zabolotskiy, Jan 04 2023

Example

1.57079632677179604650584089424649585475065931838753259598...

Mathematica

Integrate[Product[Sinc[x/(2*k+1)], {k, 0, 7}], {x, 0, Infinity}] // RealDigits[#, 10, 105]& // First

Crossrefs

Cf. A000796, A019669, A068214, A068215, A144616, A091473.

Sequence in context: A195793 A216545 A216547 * A085679 A019669 A088394

Adjacent sequences: A221205 A221206 A221207 * A221209 A221210 A221211

Keyword

cons,nonn,easy

Author

Jean-François Alcover, Feb 21 2013

Status

approved