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 A384287 #10 Jun 09 2025 10:37:53 %S A384287 3,8,8,5,6,1,8,0,8,3,1,6,4,1,2,6,7,3,1,7,3,5,5,8,4,9,6,5,6,1,2,9,3,0, %T A384287 7,7,1,4,2,6,2,2,9,1,6,7,1,6,9,2,6,4,0,9,7,5,6,8,9,0,6,3,1,7,3,2,0,9, %U A384287 7,6,6,3,7,9,4,9,4,7,6,0,5,1,8,0,0,5,1,6,7,1 %N A384287 Decimal expansion of the volume of a square orthobicupola with unit edge. %C A384287 The square orthobicupola is Johnson solid J_28. %C A384287 Also the volume of a square gyrobicupola (Johnson solid J_29) with unit edge. %H A384287 Paolo Xausa, <a href="/A384287/b384287.txt">Table of n, a(n) for n = 1..10000</a> %H A384287 Wikipedia, <a href="https://en.wikipedia.org/wiki/Square_gyrobicupola">Square gyrobicupola</a>. %H A384287 Wikipedia, <a href="https://en.wikipedia.org/wiki/Square_orthobicupola">Square orthobicupola</a>. %F A384287 Equals 2 + (4/3)*sqrt(2) = 2 + (4/3)*A002193 = 2 + A010487/3. %F A384287 Equals the largest root of 9*x^2 - 36*x + 4. %e A384287 3.885618083164126731735584965612930771426229167169... %t A384287 First[RealDigits[2 + Sqrt[32]/3, 10, 100]] (* or *) %t A384287 First[RealDigits[PolyhedronData["J28", "Volume"], 10, 100]] %Y A384287 Cf. A010469 (surface area - 10). %Y A384287 Cf. A002193, A010487, A384624. %K A384287 nonn,cons,easy %O A384287 1,1 %A A384287 _Paolo Xausa_, Jun 05 2025