A020775 Decimal expansion of 1/sqrt(18).

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

Offset

0,1

Comments

With offset 1, this is the decimal expansion of the volume of a cuboctahedron with edge length 1, which equals 5*sqrt(2)/3 = 2.357... . - Wesley Ivan Hurt, May 07 2021

Volume of a square pyramid and triangular bipyramid (Johnson solids J_1 and J_12, respectively) with unit edges. - Paolo Xausa, Aug 04 2025

Links

Ivan Panchenko, Table of n, a(n) for n = 0..1000

Wikipedia, Cuboctahedron.

Wikipedia, Square pyramid.

Wikipedia, Triangular bipyramid.

Index entries for algebraic numbers, degree 2.

Example

0.2357022603955158414669481207016163464282786458961580121961132896... - Vladimir Joseph Stephan Orlovsky, May 30 2010

Mathematica

RealDigits[N[1/Sqrt[18], 200]] (* Vladimir Joseph Stephan Orlovsky, May 30 2010 *)

Crossrefs

Cf. A343199 (cuboctahedron surface area).

Sequence in context: A124648 A093339 A113566 * A041000 A185107 A042939

Adjacent sequences: A020772 A020773 A020774 * A020776 A020777 A020778

Keyword

nonn,cons,easy

Author

N. J. A. Sloane

Status

approved