A380775 Decimal expansion of the long/short edge length ratio of a pentagonal icositetrahedron.

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

Offset: 1

Author

Paolo Xausa, Feb 02 2025

Keywords

• nonn
• cons
• easy

Examples

			1.419643377607080566275926282326643300212089373...
		

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000
• Eric Weisstein's World of Mathematics, Pentagonal Icositetrahedron.
• Wikipedia, Pentagonal icositetrahedron.

Crossrefs

Cf. A058265, A378823, A378824, A378825, A378826, A378827, A380776, A380777.

Programs

Mathematica

First[RealDigits[Root[4*#^3 - 8*#^2 + 4*# - 1 &, 1], 10, 100]]

Formula

Equals (A058265 + 1)/2.

Equals the real root of 4*x^3 - 8*x^2 + 4*x - 1.