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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.

A378391 Decimal expansion of the volume of a deltoidal icositetrahedron with unit shorter edge length.

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%I A378391 #8 Feb 11 2025 09:57:20
%S A378391 1,4,9,1,3,3,8,8,7,1,3,7,8,6,3,3,8,7,9,0,8,2,2,7,9,8,1,1,3,0,6,5,4,4,
%T A378391 8,1,0,9,4,8,2,4,4,5,1,3,5,2,1,9,9,8,0,2,4,7,7,1,9,1,7,9,1,3,1,6,4,1,
%U A378391 8,8,0,4,2,9,6,1,4,1,2,5,2,2,6,9,4,8,2,1,7,0
%N A378391 Decimal expansion of the volume of a deltoidal icositetrahedron with unit shorter edge length.
%C A378391 The deltoidal icositetrahedron is the dual polyhedron of the (small) rhombicuboctahedron.
%H A378391 Paolo Xausa, <a href="/A378391/b378391.txt">Table of n, a(n) for n = 2..10000</a>
%H A378391 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/DeltoidalIcositetrahedron.html">Deltoidal Icositetrahedron</a>.
%H A378391 Wikipedia, <a href="https://en.wikipedia.org/wiki/Deltoidal_icositetrahedron">Deltoidal icositetrahedron</a>.
%H A378391 <a href="/index/Al#algebraic_04">Index entries for algebraic numbers, degree 4</a>.
%F A378391 Equals sqrt(122 + 71*sqrt(2)) = sqrt(122 + 71*A002193).
%e A378391 14.9133887137863387908227981130654481094824451352...
%t A378391 First[RealDigits[Sqrt[122 + 71*Sqrt[2]], 10, 100]] (* or *)
%t A378391 First[RealDigits[PolyhedronData["DeltoidalIcositetrahedron", "Volume"], 10, 100]]
%Y A378391 Cf. A378390 (surface area), A378392 (inradius), A378393 (midradius), A378394 (dihedral angle).
%Y A378391 Cf. A343965 (volume of a (small) rhombicuboctahedron with unit edge).
%Y A378391 Cf. A002193.
%K A378391 nonn,cons,easy
%O A378391 2,2
%A A378391 _Paolo Xausa_, Nov 30 2024