A073746 Decimal expansion of sech(1).

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

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 A380005 A199436

Adjacent sequences: A073743 A073744 A073745 * A073747 A073748 A073749

Keyword

cons,nonn

Author

Rick L. Shepherd, Aug 07 2002

Status

approved