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A318192
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a(n) = U_{n}(n)/(n+1) where U_{n}(x) is a Chebyshev polynomial of the second kind.
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2
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1, 1, 5, 51, 781, 16005, 411881, 12776743, 464278585, 19350109449, 910126036909, 47694593157211, 2755988277318277, 174100457124362509, 11937317942278298961, 882942450221936166735, 70077737629245663437041, 5940877531422707027770385
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OFFSET
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0,3
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LINKS
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FORMULA
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a(n) = Sum_{k=0..floor(n/2)} (1/(2*k+1)) * binomial(n,2*k)*(n^2-1)^k*n^(n-2*k).
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PROG
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(PARI) {a(n) = polchebyshev(n, 2, n)/(n+1)}
(PARI) {a(n) = sum(k=0, n\2, binomial(n, 2*k)*(n^2-1)^k*n^(n-2*k)/(2*k+1))}
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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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