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A273226
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G.f. is the cube of the g.f. of A006950.
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4
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1, 3, 6, 13, 27, 51, 91, 159, 273, 455, 738, 1179, 1860, 2886, 4410, 6667, 9981, 14781, 21671, 31512, 45474, 65113, 92547, 130689, 183439, 255930, 355017, 489895, 672672, 919152, 1250107, 1692846, 2282895, 3066180, 4102224, 5468160, 7263217, 9614436, 12684633, 16682276
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OFFSET
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0,2
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LINKS
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FORMULA
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G.f.: Product_{k>=1} (1 + x^k)^3 / (1 - x^(4*k))^3, corrected by Vaclav Kotesovec, Mar 25 2017.
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MAPLE
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N:= 50:
G:= mul((1+x^k)^3, k=1..N)/mul((1-x^(4*k))^3, k=1..N/4):
S:= series(G, x, N+1):
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MATHEMATICA
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s = QPochhammer[-1, x]^3/(8*QPochhammer[x^4, x^4]^3) + O[x]^40; CoefficientList[s, x] (* Jean-François Alcover, May 20 2016 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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