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A361705
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Constant term in the expansion of (1 + w^4 + x^4 + y^4 + z^4 + 1/(w*x*y*z))^n.
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2
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1, 1, 1, 1, 1, 1, 1, 1, 1681, 15121, 75601, 277201, 831601, 2162161, 5045041, 10810801, 54054001, 592191601, 5035670641, 31553973361, 157346607601, 660308770801, 2420415874801, 7951853614321, 24853781309281, 91246800876001, 497098157556001, 3346262924004001
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OFFSET
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0,9
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LINKS
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FORMULA
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a(n) = Sum_{k=0..floor(n/8)} (4*k)!/k!^4 * binomial(8*k,4*k) * binomial(n,8*k).
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MATHEMATICA
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Table[Sum[(4*k)!/k!^4 * Binomial[8*k, 4*k] * Binomial[n, 8*k], {k, 0, n/8}], {n, 0, 30}] (* Vaclav Kotesovec, Mar 25 2023 *)
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PROG
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(PARI) a(n) = sum(k=0, n\8, (4*k)!/k!^4*binomial(8*k, 4*k)*binomial(n, 8*k));
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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