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A174994
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Repeat (8*n+4)^2.
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2
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16, 16, 144, 144, 400, 400, 784, 784, 1296, 1296, 1936, 1936, 2704, 2704, 3600, 3600, 4624, 4624, 5776, 5776, 7056, 7056, 8464, 8464, 10000, 10000, 11664, 11664, 13456, 13456, 15376, 15376, 17424, 17424, 19600, 19600, 21904, 21904, 24336, 24336, 26896, 26896, 29584, 29584, 32400, 32400, 35344, 35344
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OFFSET
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0,1
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LINKS
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FORMULA
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a(n) = a(n-1) +2*a(n-2) -2*a(n-3) -a(n-4) +a(n-5). - R. J. Mathar, Dec 02 2010
G.f.: ( -16-96*x^2-16*x^4 ) / ( (1+x)^2*(x-1)^3 ). - R. J. Mathar, Dec 02 2010
a(n) = 8*(2*n^2+2*(-1)^n*n+2*n+(-1)^n+1).
a(n) = 16*n^2+32*n+16 for n even.
a(n) = 16*n^2 for n odd. (End)
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PROG
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(PARI) Vec((-16-96*x^2-16*x^4)/((1+x)^2*(x-1)^3) + O(x^100)) \\ Colin Barker, Jan 26 2016
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CROSSREFS
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KEYWORD
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nonn,less,easy
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AUTHOR
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STATUS
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approved
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