cp's OEIS Frontend

A384283 Decimal expansion of the volume of a gyroelongated pentagonal cupola with unit edge.

%I A384283 #12 Aug 19 2025 11:29:38
%S A384283 9,0,7,3,3,3,3,1,9,3,8,8,0,1,8,7,9,9,3,1,4,9,9,8,3,9,8,1,0,1,8,1,6,2,
%T A384283 7,2,2,1,5,3,1,3,3,9,3,0,6,0,3,6,7,3,4,9,2,1,4,7,6,4,2,4,5,8,5,0,3,7,
%U A384283 6,6,8,7,2,0,6,1,5,5,3,5,4,0,3,6,2,6,2,2,8,0
%N A384283 Decimal expansion of the volume of a gyroelongated pentagonal cupola with unit edge.
%C A384283 The gyroelongated pentagonal cupola is Johnson solid J_24.
%H A384283 Paolo Xausa, <a href="/A384283/b384283.txt">Table of n, a(n) for n = 1..10000</a>
%H A384283 Wikipedia, <a href="https://en.wikipedia.org/wiki/Gyroelongated_pentagonal_cupola">Gyroelongated pentagonal cupola</a>.
%H A384283 <a href="/index/Al#algebraic_08">Index entries for algebraic numbers, degree 8</a>
%F A384283 Equals (5 + 4*sqrt(5) + 5*sqrt(2*(sqrt(650 + 290*sqrt(5)) - sqrt(5) - 1)))/6 = (5 + A010532 + 5*sqrt(2*(sqrt(650 + 290*A002163) - A002163 - 1)))/6.
%F A384283 Equals the largest real root of 1679616*x^8 - 11197440*x^7 + 27060480*x^6 + 35769600*x^5 - 4456749600*x^4 - 10714248000*x^3 + 3828402000*x^2 + 13859430000*x + 5340175625.
%e A384283 9.07333319388018799314998398101816272215313393060...
%t A384283 First[RealDigits[(5 + Sqrt[80] + 5*Sqrt[2*(Sqrt[650 + 290*Sqrt[5]] - Sqrt[5] - 1)])/6, 10, 100]] (* or *)
%t A384283 First[RealDigits[PolyhedronData["J24", "Volume"], 10, 100]]
%o A384283 (PARI) (5 + 4*sqrt(5) + 5*sqrt(2*(sqrt(650 + 290*sqrt(5)) - sqrt(5) - 1)))/6 \\ _Charles R Greathouse IV_, Aug 19 2025
%Y A384283 Cf. A384284 (surface area).
%Y A384283 Cf. A002163, A010532, A179590, A179639, A179641, A384138, A384140, A384144, A384213.
%K A384283 nonn,cons,easy
%O A384283 1,1
%A A384283 _Paolo Xausa_, May 26 2025