A344172 Decimal expansion of 4*sqrt(5 + 2*sqrt(5)).

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

Offset

2,2

Comments

Decimal expansion of the volume of a rhombic triacontahedron with unit edge length.

Links

Table of n, a(n) for n=2..94.

Wikipedia, Rhombic triacontahedron

Index entries for algebraic numbers, degree 4.

Example

12.310734148701013610281...

Mathematica

RealDigits[4 Sqrt[5 + 2 Sqrt[5]], 10, 100][[1]] // Flatten

Prog

(PARI) 4*sqrt(5+2*sqrt(5)) \\ Charles R Greathouse IV, May 18 2026

Crossrefs

Cf. A344171 (rhombic triacontahedron surface area).

Cf. A344212 (rhombic triacontahedron midradius).

Cf. A019952 (rhombic triacontahedron radius of inscribed sphere).

Sequence in context: A264433 A048994 A132393 * A395345 A121434 A296455

Adjacent sequences: A344169 A344170 A344171 * A344173 A344174 A344175

Keyword

nonn,cons

Author

Wesley Ivan Hurt, May 10 2021

Status

approved