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A073746 Decimal expansion of sech(1). 8
6, 4, 8, 0, 5, 4, 2, 7, 3, 6, 6, 3, 8, 8, 5, 3, 9, 9, 5, 7, 4, 9, 7, 7, 3, 5, 3, 2, 2, 6, 1, 5, 0, 3, 2, 3, 1, 0, 8, 4, 8, 9, 3, 1, 2, 0, 7, 1, 9, 4, 2, 0, 2, 3, 0, 3, 7, 8, 6, 5, 3, 3, 7, 3, 1, 8, 7, 1, 7, 5, 9, 5, 6, 4, 6, 7, 1, 2, 8, 3, 0, 2, 8, 0, 8, 5, 4, 7, 8, 5, 3, 0, 7, 8, 9, 2, 8, 9, 2, 3, 8, 4, 8, 4 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

sech(x) = 2/(e^x + e^(-x)).

By the Lindemann-Weierstrass theorem, this constant is transcendental. - Charles R Greathouse IV, May 14 2019

REFERENCES

Samuel M. Selby (ed.), CRC Basic Mathematical Tables, CRC Press, 1970, p. 218.

LINKS

Ivan Panchenko, Table of n, a(n) for n = 0..1000

Eric Weisstein's World of Mathematics, Hyperbolic Secant.

Eric Weisstein's World of Mathematics, Hyperbolic Functions.

Index entries for transcendental numbers

FORMULA

Equals Sum_{k>=0} E(2*k) / (2*k)!, where E(k) is the k-th Euler number (A122045). - Amiram Eldar, May 15 2021

EXAMPLE

0.64805427366388539957497735322...

MATHEMATICA

RealDigits[Sech[1], 10, 100][[1]] (* Amiram Eldar, May 15 2021 *)

PROG

(PARI) 1/cosh(1)

CROSSREFS

Cf. A068118 (continued fraction), A073743 (cosh(1)=1/A073746), A073742 (sinh(1)), A073744 (tanh(1)), A073745 (csch(1)), A073747 (coth(1)), A122045.

Sequence in context: A075495 A070652 A195487 * A010496 A199436 A035415

Adjacent sequences:  A073743 A073744 A073745 * A073747 A073748 A073749

KEYWORD

cons,nonn

AUTHOR

Rick L. Shepherd, Aug 07 2002

STATUS

approved

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Last modified January 27 22:45 EST 2022. Contains 350654 sequences. (Running on oeis4.)