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.
%I A384624 #10 Jun 09 2025 10:37:45 %S A384624 4,6,4,8,0,9,0,6,3,6,6,6,6,3,8,6,2,6,1,8,7,8,8,9,8,2,2,4,9,7,5,0,3,4, %T A384624 9,8,0,5,8,7,4,9,1,1,4,6,1,4,8,7,0,0,9,6,5,6,9,4,5,2,9,6,6,0,5,4,7,3, %U A384624 6,1,2,3,4,1,8,3,7,3,9,8,6,5,8,8,5,8,8,5,8,7 %N A384624 Decimal expansion of the volume of a pentagonal orthobicupola with unit edge. %C A384624 The pentagonal orthobicupola is Johnson solid J_30. %C A384624 Also the volume of a pentagonal gyrobicupola (Johnson solid J_31) with unit edge. %H A384624 Paolo Xausa, <a href="/A384624/b384624.txt">Table of n, a(n) for n = 1..10000</a> %H A384624 Wikipedia, <a href="https://en.wikipedia.org/wiki/Pentagonal_orthobicupola">Pentagonal orthobicupola</a>. %H A384624 Wikipedia, <a href="https://en.wikipedia.org/wiki/Pentagonal_gyrobicupola">Pentagonal gyrobicupola</a>. %F A384624 Equals (5 + 4*sqrt(5))/3 = (5 + A010532)/3. %F A384624 Equals the largest root of 9*x^2 - 30*x - 55. %e A384624 4.6480906366663862618788982249750349805874911461487... %t A384624 First[RealDigits[(5 + Sqrt[80])/3, 10, 100]] (* or *) %t A384624 First[RealDigits[PolyhedronData["J30", "Volume"], 10, 100]] %Y A384624 Cf. A384625 (surface area). %Y A384624 Cf. A010532, A384287. %K A384624 nonn,cons,easy %O A384624 1,1 %A A384624 _Paolo Xausa_, Jun 05 2025