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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.

A378393 Decimal expansion of the midradius of a deltoidal icositetrahedron with unit shorter edge length.

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%I A378393 #12 Feb 03 2025 10:02:46
%S A378393 1,5,6,0,6,6,0,1,7,1,7,7,9,8,2,1,2,8,6,6,0,1,2,6,6,5,4,3,1,5,7,2,7,3,
%T A378393 5,5,8,9,2,7,2,5,3,9,0,6,5,3,2,7,1,1,0,5,4,8,8,2,5,0,9,8,0,3,4,9,3,0,
%U A378393 4,9,3,5,8,8,4,6,5,8,0,2,7,9,1,3,7,7,9,0,6,5
%N A378393 Decimal expansion of the midradius of a deltoidal icositetrahedron with unit shorter edge length.
%C A378393 The deltoidal icositetrahedron is the dual polyhedron of the (small) rhombicuboctahedron.
%H A378393 Paolo Xausa, <a href="/A378393/b378393.txt">Table of n, a(n) for n = 1..10000</a>
%H A378393 <a href="/index/Al#algebraic_02">Index entries for algebraic numbers, degree 2</a>.
%F A378393 Equals (2 + 3*sqrt(2))/4 = (2 + A010474)/4.
%e A378393 1.5606601717798212866012665431572735589272539065327...
%t A378393 First[RealDigits[(2 + Sqrt[18])/4, 10, 100]] (* or *)
%t A378393 First[RealDigits[PolyhedronData["DeltoidalIcositetrahedron", "Midradius"], 10, 100]]
%Y A378393 Cf. A378390 (surface area), A378391 (volume), A378392 (inradius), A378394 (dihedral angle).
%Y A378393 Cf. A285871 (midradius of a (small) rhombicuboctahedron with unit edge).
%Y A378393 Cf. A010474, A093577.
%K A378393 nonn,cons,easy
%O A378393 1,2
%A A378393 _Paolo Xausa_, Nov 30 2024