A179641 Decimal expansion of the volume of pentagonal dipyramid with edge length 1.

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

Offset

0,1

Comments

Pentagonal dipyramid: 7 vertices, 15 edges, and 10 faces.

Links

Table of n, a(n) for n=0..104.

Polytope Wiki, Pentagonal tegum.

Eric Weisstein's World of Mathematics, Pentagonal Dipyramid.

Wikipedia, Pentagonal bipyramid.

Wolfram Alpha, Johnson solid 13.

Index entries for algebraic numbers, degree 2.

Formula

Equals (5+sqrt(5))/12.

Minimal polynomial: 36*x^2 - 30*x + 5. - Amiram Eldar, Jun 05 2026

Example

0.60300566479164914136743113906093968628671819663429381035590810378421...

Mathematica

RealDigits[N[(5+Sqrt[5])/12, 200]]

Prog

(PARI) (sqrt(5)+5)/12 \\ Charles R Greathouse IV, Apr 25 2016

Crossrefs

Cf. A001622, A010527, A102208, A179290, A179292, A179294, A179449-A179452, A179552-A179554, A179587-A179593, A179637-A179640.

Sequence in context: A283634 A383662 A372064 * A384466 A110993 A262697

Adjacent sequences: A179638 A179639 A179640 * A179642 A179643 A179644

Keyword

cons,nonn,easy

Author

Vladimir Joseph Stephan Orlovsky, Jul 21 2010

Extensions

Offset corrected by R. J. Mathar, Aug 15 2010

Status

approved