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 A385509 #10 Jul 02 2025 16:54:40 %S A385509 1,9,5,6,1,7,9,6,6,0,9,8,4,4,8,2,7,6,4,2,2,5,9,6,0,0,9,8,0,9,0,2,2,5, %T A385509 9,4,5,8,3,5,6,5,2,8,1,5,9,0,6,3,5,6,3,4,1,4,0,3,2,0,7,9,9,6,6,8,8,9, %U A385509 9,1,0,7,1,9,5,2,6,5,0,7,3,7,8,0,7,5,0,5,8,3 %N A385509 Decimal expansion of the volume of an augmented pentagonal prism with unit edge. %C A385509 The augmented pentagonal prism is Johnson solid J_52. %H A385509 Paolo Xausa, <a href="/A385509/b385509.txt">Table of n, a(n) for n = 1..10000</a> %H A385509 Wikipedia, <a href="https://en.wikipedia.org/wiki/Augmented_pentagonal_prism">Augmented pentagonal prism</a>. %F A385509 Equals sqrt(233 + 90*sqrt(5) + 12*sqrt(50 + 20*sqrt(5)))/12 = sqrt(233 + 90*A002163 + 12*sqrt(50 + 20*A002163))/12. %F A385509 Equals the largest root of 429981696*x^8 - 2782937088*x^6 + 4776205824*x^4 - 1630792512*x^2 + 43414921. %e A385509 1.9561796609844827642259600980902259458356528159... %t A385509 First[RealDigits[Sqrt[233 + 90*Sqrt[5] + 12*Sqrt[50 + 20*Sqrt[5]]]/12, 10, 100]] (* or *) %t A385509 First[RealDigits[PolyhedronData["J52", "Volume"], 10, 100]] %Y A385509 Cf. A385510 (surface area). %Y A385509 Cf. A002163. %K A385509 nonn,cons,easy %O A385509 1,2 %A A385509 _Paolo Xausa_, Jul 01 2025