A321209 - OEIS

A321209

Decimal expansion of the volume of the Löbell polyhedron L(5).

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

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..100.

Taiyo Inoue, Organizing Volumes of Right-Angled Hyperbolic Polyhedra, arXiv:0809.2111 [math.GT], 2008.

EXAMPLE

4.3062076007308086529198371598422094492411852354129341142249491178199...

MATHEMATICA

theta[n_] := Pi/2 - ArcCos[1/(2 Cos[Pi/n])];

lambda[z_] := -Integrate[Log[Abs[2 Sin[t]]], {t, 0, z}];

vol[n_] := n/2 (2 lambda[theta[n]] + lambda[theta[n] + Pi/n] + lambda[theta[n] - Pi/n] - lambda[2 theta[n] - Pi/2]);