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A001237
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Differences of reciprocals of unity.
(Formerly M5229 N2276)
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2
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31, 3661, 1217776, 929081776, 1413470290176, 3878864920694016, 17810567950611972096, 129089983180418186674176, 1409795030885143760732160000, 22335321387514981111936450560000, 497400843208278958640564703068160000, 15161356456130244705175927906904309760000
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OFFSET
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1,1
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REFERENCES
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F. N. David, M. G. Kendall and D. E. Barton, Symmetric Function and Allied Tables, Cambridge, 1966, p. 228.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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FORMULA
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a(n) = (n + 1)!^4/480*(20*Psi(n + 2)^4 + 80*gamma*Psi(n + 2)^3 - 120*Psi(n + 2)^2*Psi(1, n + 2) + 20*Pi^2*Psi(n + 2)^2 + 120*gamma^2*Psi(n + 2)^2 - 240*gamma*Psi(n + 2)*Psi(1, n + 2) + 80*Psi(n + 2)*Psi(2, n + 2) + 60*Psi(1, n + 2)^2 + 40*gamma*Pi^2*Psi(n + 2) + 160*Zeta(3)*Psi(n + 2) + 80*gamma^3*Psi(n + 2) - 20*Pi^2*Psi(1, n + 2) - 120*gamma^2*Psi(1, n + 2) + 80*gamma*Psi(2, n + 2) - 20*Psi(3, n + 2) + 160*gamma*Zeta(3) + 3*Pi^4 + 20*gamma^4 + 20*gamma^2*Pi^2). - Vladeta Jovovic, Aug 10 2002
a(n) = (n+1)!^4 * Sum[i=1..n+1, Sum[j=1..i, Sum[k=1..j, Sum[l=1..k, 1/(ijkl) ]]].
a(n) = ((n+1)!)^4 * sum((-1)^(k+1)*C(n+1,k)/k^4,k=1..n+1). - Sean A. Irvine, Mar 29 2012
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MATHEMATICA
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a[n_] := -(Factorial[n + 1]^4)*Sum[(-1)^k Binomial[n + 1, k]/k^4, {k, 1, n + 1}]; Table[a[n], {n, 14}] (* James C. McMahon, Dec 12 2023 *)
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PROG
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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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