A347903 Decimal expansion of the surface area of the unit trihyperboloid.

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

Offset: 2

Author

Eric W. Weisstein, Sep 18 2021

Keywords

• nonn
• cons

Examples

			18.769396267453...
		

Links

• Eric Weisstein's World of Mathematics, Trihyperboloid

Crossrefs

Cf. A257872 (volume of the unit trihyperboloid).

Programs

Mathematica

First[RealDigits[N[24(Sqrt[3]-1)-2Pi+12Sqrt[2]Re[NIntegrate[ArcTanh[x]/((2x^2-1)Sqrt[(1-x^(-2))/2]),{x,Sqrt[3/2],Infinity},WorkingPrecision->100]],90]]] (* Stefano Spezia, Sep 19 2021 *)

Formula

Can be given as a closed-form expression involving logs, polylogs, and polygammas (which probably simplifies further).