A386752 Decimal expansion of the volume of a disphenocingulum with unit edges.

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

Offset: 1

Author

Paolo Xausa, Aug 01 2025

Keywords

• nonn
• cons
• easy

Comments

The disphenocingulum is Johnson solid J_90.

Examples

			3.7776453418585752428818131132610964733952267025...
		

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000
• Wikipedia, Disphenocingulum.

Crossrefs

Cf. A385257 (surface area + 2).

Programs

Mathematica

First[RealDigits[Root[1213025622610333925376*#^24 + 54451372392730545094656*#^22 - 796837093078664749252608*#^20 - 4133410366404688544268288*#^18 + 20902529024429842816303104*#^16 - 133907540390420673677230080*#^14 + 246234688242991598853881856*#^12 - 63327534106871321714442240*#^10 + 14389309497459555704164608*#^8 + 48042947402464500749392128*#^6 - 5891096640600351061013664*#^4 - 3212114716816853362953264*#^2 + 479556973248657693884401 &, 8], 10, 100]] (* or *)
First[RealDigits[PolyhedronData["J90", "Volume"], 10, 100]]

Formula

Equals the largest real root of 1213025622610333925376*x^24 + 54451372392730545094656*x^22 - 796837093078664749252608*x^20 - 4133410366404688544268288*x^18 + 20902529024429842816303104*x^16 - 133907540390420673677230080*x^14 + 246234688242991598853881856*x^12 - 63327534106871321714442240*x^10 + 14389309497459555704164608*x^8 + 48042947402464500749392128*x^6 - 5891096640600351061013664*x^4 - 3212114716816853362953264*x^2 + 479556973248657693884401.