A343745 Decimal expansion of 12*sqrt(25+10*sqrt(5))/(15+7*sqrt(5)).

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

Offset

1,1

Comments

Surface area to volume ratio of a dodecahedron with unit side length.

Links

Table of n, a(n) for n=1..94.

Wikipedia, Surface-area-to-volume ratio.

Index entries for algebraic numbers, degree 4.

Formula

Minimal polynomial: x^4 - 900*x^2 + 6480. - Amiram Eldar, May 26 2026

Example

2.694167859477512234651670...

Mathematica

RealDigits[12 Sqrt[25 + 10 Sqrt[5]]/(15 + 7 Sqrt[5]), 10, 100] // Flatten

Prog

(PARI) 12*sqrt(25+10*sqrt(5))/(15+7*sqrt(5)) \\ Charles R Greathouse IV, May 18 2026

Crossrefs

Cf. A343864.

Sequence in context: A179275 A215498 A104752 * A183000 A170821 A096667

Adjacent sequences: A343742 A343743 A343744 * A343746 A343747 A343748

Keyword

nonn,cons

Author

Wesley Ivan Hurt, May 02 2021

Status

approved