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A016743
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Even cubes: a(n) = (2*n)^3.
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11
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0, 8, 64, 216, 512, 1000, 1728, 2744, 4096, 5832, 8000, 10648, 13824, 17576, 21952, 27000, 32768, 39304, 46656, 54872, 64000, 74088, 85184, 97336, 110592, 125000, 140608, 157464, 175616, 195112, 216000, 238328, 262144, 287496, 314432
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OFFSET
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0,2
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COMMENTS
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a(n) is also the number of non-degenerate triangles that can be drawn with vertices on a cross with n points on each branch. - James P. B. Hall, Nov 22 2019
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LINKS
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Hilko Koning, 216 neodymium magnets for n=3.
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FORMULA
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a(n) = (2*n)^3 = 8*n^3.
G.f.: x*(8+32*x+8*x^2)/(1-4*x+6*x^2-4*x^3+x^4). - Colin Barker, Jan 02 2012
Sum_{n>=1} 1/a(n) = zeta(3)/8 (A276712).
Sum_{n>=1} (-1)^(n+1)/a(n) = 3*zeta(3)/32. (End)
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MAPLE
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MATHEMATICA
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PROG
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CROSSREFS
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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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