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A034824
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Number of n-node rooted trees of height at most 7.
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4
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1, 1, 1, 2, 4, 9, 20, 48, 115, 285, 710, 1789, 4514, 11431, 28922, 73182, 184917, 466755, 1176393, 2961205, 7443770, 18689435, 46869152, 117412440, 293832126, 734645046, 1835147741, 4580420719, 11423511895, 28469058647, 70899220083, 176449174539, 438854372942
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OFFSET
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0,4
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LINKS
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FORMULA
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MAPLE
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For Maple program see link in A000235.
with(numtheory): etr:= proc(p) local b; b:=proc(n) option remember; local d, j; if n=0 then 1 else add(add(d*p(d), d=divisors(j)) *b(n-j), j=1..n)/n fi end end: shr:= proc(p) n->`if`(n=0, 1, p(n-1)) end: b[0]:= etr(n->1): for j from 1 to 5 do b[j]:= etr(shr(b[j-1])) od: a:= shr(b[5]): seq(a(n), n=0..35); # Alois P. Heinz, Sep 08 2008
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MATHEMATICA
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Prepend[Nest[CoefficientList[Series[Product[1/(1-x^i)^#[[i]], {i, 1, Length[#]}], {x, 0, 40}], x]&, {1}, 7], 1] (* Geoffrey Critzer, Aug 01 2013 *)
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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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