A038090 Number of n-node rooted identity trees of height 6.
1, 5, 14, 33, 72, 149, 301, 599, 1170, 2254, 4288, 8081, 15087, 27971, 51500, 94293, 171724, 311328, 562023, 1010819, 1811676, 3236959, 5766793, 10246734, 18162241, 32119542, 56682671, 99833464, 175509158, 308014335, 539675744, 944115593, 1649236884
Offset: 7
Links
Programs
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Maple
weigh:= proc(p) proc(n) local x, k; coeff(series(mul((1+x^k)^p(k), k=1..n), x,n+1), x,n) end end: wsh:= p-> n-> weigh(p)(n-1): f:= n-> `if`(n>0 and n<12, [1$3, 2$5, 1$3][n], 0): a:= (wsh@@3)(f)-(wsh@@2)(f): seq(a(n), n=7..37); # Alois P. Heinz, Sep 10 2008
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Mathematica
f[n_]:=Nest[CoefficientList[Series[Product[(1+x^i)^#[[i]],{i,1,Length[#]}],{x,0,50}],x]&,{1},n];Drop[f[6]-PadRight[f[5],Length[f[6]]],6] (* Geoffrey Critzer, Aug 01 2013 *)
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