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A341386
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Expansion of (-1 + Product_{k>=1} (1 + x^k)^k)^4.
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10
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1, 8, 44, 184, 662, 2120, 6256, 17276, 45277, 113568, 274592, 643220, 1465838, 3260428, 7097338, 15153288, 31791822, 65645360, 133584864, 268213400, 531879490, 1042657088, 2022113788, 3882468712, 7384455791, 13921287616, 26026092198, 48273051172, 88868177735
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OFFSET
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4,2
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LINKS
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MAPLE
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g:= proc(n) option remember; `if`(n=0, 1, add(g(n-j)*add(d^2/
`if`(d::odd, 1, 2), d=numtheory[divisors](j)), j=1..n)/n)
end:
b:= proc(n, k) option remember; `if`(k=0, 1, `if`(k=1, `if`(n=0, 0,
g(n)), (q-> add(b(j, q)*b(n-j, k-q), j=0..n))(iquo(k, 2))))
end:
a:= n-> b(n, 4):
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MATHEMATICA
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nmax = 32; CoefficientList[Series[(-1 + Product[(1 + x^k)^k, {k, 1, nmax}])^4, {x, 0, nmax}], x] // Drop[#, 4] &
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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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