A394808 Decimal expansion of Pi - 4/Pi.

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

Offset

1,2

Comments

The mean geodesic distance between two points chosen independently and uniformly at random, one from each of the two sides of a given equator of a unit sphere.

References

Luis A. Santaló, Integral Geometry and Geometric Probability, 2nd ed., Cambridge University Press, 2004, p. 313, note 6.

Links

Table of n, a(n) for n=1..105.

John W. Berry, Problem 194, The Mathematical Visitor, Vol. 1, No. 4 (1880), p. 116.

Enoch B. Seitz, Solution to Problem 194, The Mathematical Visitor, Vol. 2, No. 1 (1882), p. 15.

Index entries for transcendental numbers.

Formula

Equals A000796 - A088538 = 2 * A019669 - A088538.

Example

1.868353108854630552311573276299387987921492233451454...

Mathematica

RealDigits[Pi - 4/Pi, 10, 120][[1]]

Prog

(PARI) Pi - 4/Pi

Crossrefs

Cf. A000796, A088538, A019669.

Cf. A394809, A394810, A394811, A394812.

Sequence in context: A302682 A384476 A011298 * A355185 A381688 A389953

Adjacent sequences: A394805 A394806 A394807 * A394809 A394810 A394811

Keyword

nonn,cons

Author

Amiram Eldar, Apr 02 2026

Status

approved