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A308666 Decimal expansion of sinh(sqrt(2)*Pi)/(3*sqrt(2)*Pi). 2
3, 1, 8, 8, 9, 1, 7, 8, 8, 7, 5, 4, 8, 9, 6, 2, 4, 2, 2, 2, 8, 5, 9, 3, 8, 6, 1, 6, 6, 6, 5, 0, 9, 6, 7, 5, 2, 4, 0, 6, 5, 2, 9, 5, 9, 5, 1, 4, 2, 9, 9, 2, 4, 7, 5, 8, 9, 2, 5, 6, 0, 8, 7, 1, 7, 7, 8, 2, 2, 0, 7, 2, 8, 1, 2, 2, 8, 7, 0, 3, 1, 1, 7, 9, 0, 5, 3, 8, 8, 7, 1, 6, 4, 6, 5, 2, 3, 2, 5, 2, 6, 6, 3, 1, 1, 2, 4, 7, 8, 2, 5, 6, 5, 2, 3, 2, 3, 3, 6, 6 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Equals Product_{k>=1} (1 + 1/(k*(k + 1)*(k + 2)/6)).

Equals Product_{k>=1} (1 + 1/A000292(k)).

Equals Product_{k>=2} (1 + 2/k^2). - Amiram Eldar, Aug 02 2020

EXAMPLE

3.188917887548962422285938616665096752406529595142992...

MATHEMATICA

RealDigits[Sinh[Sqrt[2] Pi]/(3 Sqrt[2] Pi), 10, 120][[1]]

RealDigits[Product[(1 + 1/(k (k + 1) (k + 2)/6)), {k, 1, Infinity}], 10, 120][[1]]

PROG

(PARI) sinh(sqrt(2)*Pi)/(3*sqrt(2)*Pi) \\ Michel Marcus, Jun 15 2019

CROSSREFS

Cf. A000292, A084248, A308642.

Sequence in context: A245651 A007023 A176103 * A076238 A008298 A039692

Adjacent sequences:  A308663 A308664 A308665 * A308667 A308668 A308669

KEYWORD

nonn,cons

AUTHOR

Ilya Gutkovskiy, Jun 15 2019

STATUS

approved

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Last modified April 11 18:00 EDT 2021. Contains 342888 sequences. (Running on oeis4.)