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A089836
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INVERT transform of A089835.
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2
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2, 28, 704, 26800, 1404416, 94890112, 7887853568, 779773444864, 89407927009280, 11666949886007296, 1707352344419336192, 276938622991133237248, 49316570352062326636544, 9565558797749164794511360, 2007400581177856844629016576, 453192947995950052758954115072
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,1
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LINKS
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FORMULA
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MAPLE
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a:= proc(n) option remember; local i; `if`(n<1, 1, add(a(n-i) *(2*i)!^2 /i!^3 /(i+1), i=1..n)) end: seq(a(n), n=1..20); # Alois P. Heinz, Apr 01 2009
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MATHEMATICA
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a[n_] := a[n] = If[n < 1, 1, Sum[a[n - i] *(2 i)!^2 /i!^3 /(i + 1), {i, 1, n}]]; Array[a, 20] (* Jean-François Alcover, Mar 03 2016, adapted from Maple *)
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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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