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A152750
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Eight times hexagonal numbers: 8*n*(2*n-1).
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5
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0, 8, 48, 120, 224, 360, 528, 728, 960, 1224, 1520, 1848, 2208, 2600, 3024, 3480, 3968, 4488, 5040, 5624, 6240, 6888, 7568, 8280, 9024, 9800, 10608, 11448, 12320, 13224, 14160, 15128, 16128, 17160, 18224, 19320, 20448, 21608, 22800, 24024, 25280, 26568
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OFFSET
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0,2
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COMMENTS
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Equals Engel expansion of cosh(1/2), except first member (see A067239).
Also sequence found by reading the line from 0, in the direction 0, 8, ..., in the square spiral whose vertices are the generalized decagonal numbers A074377. - Omar E. Pol, Sep 18 2011
a(n) = the sum of the edges of a rectangular prism having edges 2*(n-1)*n, n^2-(n-1)^2 and n^2 + (n-1)^2. - J. M. Bergot, Apr 24 2014
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LINKS
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FORMULA
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a(n) = 3*a(n-1)-3*a(n-2)+a(n-3) for n>2.
G.f.: 8*x*(1+3*x) / (1-x)^3.
(End)
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MAPLE
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MATHEMATICA
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PROG
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(PARI) concat(0, Vec(8*x*(1+3*x)/(1-x)^3 + O(x^50))) \\ Colin Barker, Sep 25 2016
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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