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A203167
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(n-1)-st elementary symmetric function of the first n terms of (2,2,1,2,2,1,2,2,1,...)=(A130196 for n>0).
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1
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1, 4, 8, 20, 48, 64, 144, 320, 384, 832, 1792, 2048, 4352, 9216, 10240, 21504, 45056, 49152, 102400, 212992, 229376, 475136, 983040, 1048576, 2162688, 4456448, 4718592, 9699328, 19922944, 20971520, 42991616, 88080384, 92274688, 188743680
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OFFSET
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1,2
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LINKS
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FORMULA
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Conjecture: a(n) = 8*a(n-3) - 16*a(n-6).
Conjecture: G.f.: x*(1+4*x+8*x^2+12*x^3+16*x^4) / (-1+4*x^3)^2.
(End)
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MATHEMATICA
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f[k_] := 1 + Mod[k^2, 3]; t[n_] := Table[f[k], {k, 1, n}]
a[n_] := SymmetricPolynomial[n - 1, t[n]]
Table[a[n], {n, 1, 33}] (* A203167 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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