A384036 Decimal expansion of the surface area of a regular pentagonal prism of edge length 1.

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

Offset

1,1

Links

Table of n, a(n) for n=1..87.

Formula

Equals 5 + (1/2)*sqrt(25 + 10*sqrt(5)).

Minimal polynomial: 16*x^4 - 320*x^3 + 2200*x^2 - 6000*x + 5125. - Stefano Spezia, May 17 2025

Example

8.4409548011779338455...

Mathematica

RealDigits[5 + 1/2 * Sqrt(25 + 10 * Sqrt(5)), 10, 100, 0][[1]]

Crossrefs

Cf. A178809.

Cf. A102771 (volume), A300074 (midradius), A384059 (circumradius).

Sequence in context: A388746 A388675 A019723 * A388378 A093822 A356810

Adjacent sequences: A384033 A384034 A384035 * A384037 A384038 A384039

Keyword

nonn,cons

Author

Kritsada Moomuang, May 17 2025

Status

approved