cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A384141 Decimal expansion of the surface area of an elongated pentagonal bipyramid with unit edge.

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%I A384141 #9 May 22 2025 05:19:54
%S A384141 9,3,3,0,1,2,7,0,1,8,9,2,2,1,9,3,2,3,3,8,1,8,6,1,5,8,5,3,7,6,4,6,8,0,
%T A384141 9,1,7,3,5,7,0,1,3,1,3,4,5,2,5,9,5,1,5,7,0,1,3,9,5,1,7,4,4,8,6,2,9,8,
%U A384141 3,2,5,4,2,2,7,2,0,0,0,0,9,2,7,0,2,8,6,5,4,6
%N A384141 Decimal expansion of the surface area of an elongated pentagonal bipyramid with unit edge.
%C A384141 The elongated pentagonal bipyramid is Johnson solid J_16.
%H A384141 Paolo Xausa, <a href="/A384141/b384141.txt">Table of n, a(n) for n = 1..10000</a>
%H A384141 Wikipedia, <a href="https://en.wikipedia.org/wiki/Elongated_pentagonal_bipyramid">Elongated pentagonal bipyramid</a>.
%F A384141 Equals 5*(2 + sqrt(3))/2 = 5*(2 + A002194)/2.
%F A384141 Equals the largest root of 4*x^2 - 40*x + 25.
%e A384141 9.3301270189221932338186158537646809173570131345...
%t A384141 First[RealDigits[5*(2 + Sqrt[3])/2, 10, 100]] (* or *)
%t A384141 First[RealDigits[PolyhedronData["J16", "SurfaceArea"], 10, 100]]
%Y A384141 Cf. A384140 (volume).
%Y A384141 Cf. A002163.
%Y A384141 Essentially the same as A120011.
%K A384141 nonn,cons,easy
%O A384141 1,1
%A A384141 _Paolo Xausa_, May 20 2025