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0, 9, 72, 243, 576, 1125, 1944, 3087, 4608, 6561, 9000, 11979, 15552, 19773, 24696, 30375, 36864, 44217, 52488, 61731, 72000, 83349, 95832, 109503, 124416, 140625, 158184, 177147, 197568, 219501, 243000, 268119, 294912, 323433, 353736, 385875, 419904
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OFFSET
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0,2
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COMMENTS
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Volume of a pyramid (square base) with side and height 3*n. - Wesley Ivan Hurt, Aug 25 2014
Volume of the smallest square cuboid containing a ring torus where the tube and hole diameters are both n. - Torlach Rush, Jun 04 2019
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LINKS
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FORMULA
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G.f.: 9*x*(1 + 4*x + x^2)/(1 - x)^4.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n>3.
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MAPLE
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MATHEMATICA
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Table[9n^3, {n, 0, 40}] (* or *) CoefficientList[Series[9*x*(1+4*x+x^2)/(1- x)^4, {x, 0, 40}], x]
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PROG
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(Magma) [9*n^3: n in [0..40]] /* or */ I:=[0, 9, 72, 243]; [n le 4 select I[n] else 4*Self(n-1)-6*Self(n-2)+4*Self(n-3)-Self(n-4): n in [1..40]];
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CROSSREFS
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Cf. similar sequences listed in A244725.
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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