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A203677
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Vandermonde sequence using x^2 + y^2 applied to (1,4,9,...,n^2).
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4
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OFFSET
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1,2
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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) ~ c * 2^(n^2/2 - 1) * (1 + sqrt(2))^(n*(n+1)/sqrt(2)) * exp((Pi/2^(3/2) - 3)*n^2 + (Pi/2^(3/2) + 2)*n) * n^(2*n^2 - 2*n - 3/2), where c = 0.154147406559582639039828423669556073435424655001221440918550218582474208... - Vaclav Kotesovec, Sep 08 2023
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MATHEMATICA
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f[j_] := j^2; 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}] (* A203677 *)
Table[v[n + 1]/v[n], {n, 1, z}] (* A203678 *)
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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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