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A203684
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v(n+1)/v(n), where v=A203683.
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2
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5, 340, 353600, 5816012800, 1526121758720000, 6402581345767260160000, 429696185755224300427673600000, 461389806400964771465272438344908800000, 7926646754442012918793099237780758028353536000000
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OFFSET
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1,1
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COMMENTS
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See A093883 for a discussion and guide to related sequences.
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LINKS
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FORMULA
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a(n) = ((5*4^(n*(n+1)))/(4^(n+1)+1))*(-4^-(n+1);4)_n, where the q-Pochhammer symbol (c;q)_m = product(1-c*q^j, j = 0..m-1). - Todd Silvestri, Nov 16 2014
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MAPLE
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f:= n -> ((5*4^(n*(n+1)))/(4^(n+1)+1))*mul(1+4^(k-(n+1)), k=0..n-1);
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MATHEMATICA
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f[j_] := 2^(j - 1); z = 12;
u[n_] := Product[f[j]^2 + f[k]^2, {j, 1, k - 1}]
v[n_] := Product[u[n], {k, 2, n}]
Table[v[n], {n, 1, z}] (* A203683 *)
Table[v[n + 1]/v[n], {n, 1, z}] (* A203684 *)
a[n_Integer/; n>=1]:=(5 4^(n (n+1)))/(4^(n+1)+1) QPochhammer[-4^-(n+1), 4, n] (* Todd Silvestri, Nov 16 2014 *)
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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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