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A092974
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Row 9 of array in A288580.
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7
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1, 1, 2, 3, 4, -20, -18, -14, -8, -81, -80, -154, -216, -260, 3640, 3240, 2464, 1360, 26244, 25840, 49280, 68040, 80080, -1841840, -1632960, -1232000, -671840, -19131876, -18811520, -35728000, -48988800, -57097040, 1827105280, 1616630400, 1214752000, 658403200, 24794911296, 24360918400
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,3
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REFERENCES
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F. Smarandache, Back and Forth Factorials, Arizona State Univ., Special Collections, 1972.
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LINKS
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FORMULA
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a(n, k) = !n!_k = Prod_{i=0, 1, 2, .., floor(2n/k)}_{0<|n-i*k|<=n} (n-i*k) = n(n-k)(n-2k)(n-3k)... . k=9.
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MAPLE
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T:=proc(n, k) local i, p;
p:=1;
for i from 0 to floor(2*n/k) do
if n-k*i <> 0 then p:=p*(n-k*i) fi; od:
p;
end;
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PROG
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(PARI) a(n, k)=prod(j=0, (2*n)\k, if(n-k*j==0, 1, n-k*j))
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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