A367960 Decimal expansion of tanh(Pi/2).

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

Offset: 0

Author

R. J. Mathar, Dec 06 2023

Keywords

• nonn
• cons

Examples

			0.91715233566727434637309...
		

References

• Calvin C. Clawson, Mathematical Mysteries: The Beauty and Magic of Numbers, Springer, 2013. See p. 225.

Crossrefs

Cf. A367961, A367959, A308715, A083124 (cont. frac).

Programs

Maple

evalf(tanh(Pi/2)) ;

Mathematica

First[RealDigits[Tanh[Pi/2],10,100]] (* Paolo Xausa, Dec 06 2023 *)

Formula

Equals 1/A367961 = A367959 / A308715 = (2/Pi)*A228048.

Equals (e^Pi - 1)/(e^Pi + 1) = K_{n>0} Pi^(2-[n=1])/(4*n - 2) (see Clawson at p. 225). - Stefano Spezia, Jul 01 2024