A395537 Decimal expansion of the sum of the reciprocals of hexagonal polygorials A000680.

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

Offset

1,1

Comments

The expected number of points that are independently and uniformly selected at random in a unit disk until the sum of their distances from the center exceeds 1. - Amiram Eldar, Jun 09 2026

Links

Kelvin Voskuijl, Table of n, a(n) for n = 1..20000

Michael I. Shamos, A catalog of the real numbers, (2007). See p. 222.

Formula

Equals cosh(sqrt(2)).

Example

2.178183556608570863989222067820125283...

Mathematica

RealDigits[Cosh[Sqrt[2]], 10, 120][[1]]

Prog

(PARI) cosh(sqrt(2)) \\ Stefano Spezia, Apr 28 2026

Crossrefs

Cf. A001113 (of factorials), A070910 (of factorials squared).

Cf. A395536-A395538 (pentagonal and heptagonal).

Cf. A000680.

Sequence in context: A256392 A011134 A157240 * A395695 A144749 A021463

Adjacent sequences: A395534 A395535 A395536 * A395538 A395539 A395542

Keyword

nonn,cons,changed

Author

Kelvin Voskuijl, Apr 27 2026

Status

approved