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%I #39 Jan 14 2020 00:55:31
%S 0,44,2320,54800,1146112,23278472,468028264,9376805048,187644496672,
%T 3753613318520,75077089399408,1501573939443704,30031693123408792,
%U 600635291349699440,12012715352891236816,240254370564131706488,4805087834658423387496,96101759515675744360544
%N Number of level-n cubes on a Menger Sponge that are enclosed in the inscribed sphere of the starting cube.
%C A level-n cube is understood to be enclosed in a sphere if each of its 8 vertices lies either inside or on the surface of the sphere.
%C This sequence is a 3D extension to A293288.
%H Sierpinski copper coin, <a href="https://emathgroup.github.io/blog/xebsj-coin#menger">Table of results computed by Hong Yang Cao</a> (in Chinese).
%H Wikipedia, <a href="https://en.wikipedia.org/wiki/Menger_sponge">Menger sponge</a>.
%Y Cf. A117609, A120884, A293288.
%K nonn
%O 1,2
%A _Zhao Hui Du_, Nov 30 2019
%E a(9)-a(18) from Ickiverar added by _Zhao Hui Du_, Jan 10 2020
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