A308716 Decimal expansion of 2*sinh(Pi/2)/Pi.

1, 4, 6, 5, 0, 5, 2, 3, 8, 3, 3, 3, 6, 6, 3, 4, 8, 7, 7, 6, 0, 9, 1, 7, 9, 3, 7, 4, 1, 1, 2, 6, 5, 1, 0, 0, 7, 8, 1, 9, 9, 3, 4, 2, 6, 4, 1, 6, 7, 3, 4, 0, 8, 7, 1, 8, 3, 9, 5, 9, 0, 9, 1, 2, 3, 2, 5, 3, 9, 7, 3, 8, 5, 9, 5, 3, 6, 8, 7, 2, 1, 6, 5, 9, 9, 2, 8, 8, 7, 4, 2, 8, 7, 1, 0, 7, 5, 8, 6, 0, 0, 1, 9, 5, 1, 8, 7, 3, 4, 1, 8, 3, 0, 4, 3, 1, 5, 6, 9, 8

Offset

1,2

Links

Table of n, a(n) for n=1..120.

Formula

Equals Product_{k>=1} (1 + 1/(4*k^2)).

Equals Product_{k>=1} (1 + 1/A016742(k)).

Equals binomial(0, i/2), where i is the imaginary unit. - Amiram Eldar, Nov 25 2020

Example

1.465052383336634877609179374112651007819934264167...

Mathematica

RealDigits[2 Sinh[Pi/2]/Pi, 10, 120][[1]]

Prog

(PARI) 2*sinh(Pi/2)/Pi \\ Michel Marcus, Jun 20 2019

Crossrefs

Cf. A016742, A060294, A156648, A308715.

Sequence in context: A019089 A173462 A019123 * A021219 A200127 A222069

Adjacent sequences: A308713 A308714 A308715 * A308717 A308718 A308719

Keyword

nonn,cons

Author

Ilya Gutkovskiy, Jun 19 2019

Status

approved