A038091 Number of n-node rooted identity trees of height 7.

1, 6, 20, 54, 132, 303, 672, 1460, 3120, 6575, 13707, 28296, 57938, 117764, 237878, 477781, 954910, 1899930, 3765054, 7433724, 14628436, 28698388, 56143591, 109550807, 213251179, 414190801, 802808056, 1553046868, 2998986556, 5781366468, 11127506290

Offset: 8

Author

Christian G. Bower, Jan 04 1999

Keywords

• nonn
• fini

Comments

The number of terms with a(n)>0 is A038093(7) - 7. - Alois P. Heinz, Sep 22 2013

Links

• Alois P. Heinz, Table of n, a(n) for n = 8..1000
• Index entries for sequences related to rooted trees

Crossrefs

Cf. A038081-A038093.

Column k=7 of A227819.

Programs

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@@4)(f)-(wsh@@3)(f): seq(a(n), n=8..36);  # Alois P. Heinz, Sep 10 2008

Mathematica

f[n_]:=Nest[CoefficientList[Series[Product[(1+x^i)^#[[i]],{i,1,Length[#]}],{x,0,50}],x]&,{1},n];Drop[f[7]-PadRight[f[6],Length[f[7]]],7] (* Geoffrey Critzer, Aug 01 2013 *)

Formula

A038086 - A038085.