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A348704
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a(n) = Sum_{x_1+x_2+ ... +x_n=n, 0 <= x_1<= x_2 <= ... <= x_n <= n} ((n-1)*n)!/((n-x_1)! * (n-x_2)! * ... * (n-x_n)!).
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3
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1, 1, 3, 170, 1027950, 1079901406584, 448687115051986530720, 89290138377185872821028908288000, 14759276773881730859717740767606565269685350000, 2387650794422480788739162652666454048976136433287918499830000000
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listen;
history;
text;
internal format)
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OFFSET
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0,3
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LINKS
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PROG
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(Ruby)
def f(n)
return 1 if n < 2
(1..n).inject(:*)
end
def A(k, n)
sum = 0
m = f((k - 1) * n)
(0..n).to_a.repeated_combination(k){|i|
if (0..k - 1).inject(0){|s, j| s + i[j]} == n
sum += m / (0..k - 1).inject(1){|s, j| s * f(n - i[j])}
end
}
sum
end
(0..n).map{|i| A(i, i)}
end
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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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