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0, 7, 56, 189, 448, 875, 1512, 2401, 3584, 5103, 7000, 9317, 12096, 15379, 19208, 23625, 28672, 34391, 40824, 48013, 56000, 64827, 74536, 85169, 96768, 109375, 123032, 137781, 153664, 170723, 189000, 208537, 229376, 251559, 275128, 300125, 326592, 354571, 384104
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OFFSET
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0,2
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COMMENTS
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Volume of a truncated square pyramid with base lengths n and 2n, and height 3n. - Wesley Ivan Hurt, Apr 05 2016
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LINKS
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FORMULA
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G.f.: 7*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[7 n^3, {n, 0, 40}] (* or *) CoefficientList[Series[7 x (1 + 4 x + x^2)/(1 - x)^4, {x, 0, 40}], x]
LinearRecurrence[{4, -6, 4, -1}, {0, 7, 56, 189}, 40] (* Harvey P. Dale, Apr 04 2024 *)
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PROG
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(Magma) [7*n^3: n in [0..40]] /* or */ I:=[0, 7, 56, 189]; [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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