This site is supported by donations to The OEIS Foundation.



Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 4500 articles have referenced us, often saying "we would not have discovered this result without the OEIS".

(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A038084 Number of n-node rooted identity trees of height at most 5. 4


%S 1,1,1,2,3,6,11,19,31,52,85,140,228,370,594,954,1519,2412,3814,6006,

%T 9419,14726,22938,35612,55125,85065,130900,200875,307446,469342,

%U 714784,1085956,1646160,2489838,3757929,5660110,8508224,12764585,19114360,28570525,42629077

%N Number of n-node rooted identity trees of height at most 5.

%C A finite sequence with A038093(5) = 3211265 terms.

%H Alois P. Heinz, <a href="/A038084/b038084.txt">Table of n, a(n) for n = 1..1000</a>

%H N. J. A. Sloane, <a href="/transforms.txt">Transforms</a>

%H <a href="/index/Ro#rooted">Index entries for sequences related to rooted trees</a>

%F Take Weigh transform of A038083 and shift right.

%p weigh:= proc(p) proc(n) `if`(n<0, 1, coeff(mul((1+x^k)^p(k), k=1..n), x,n)) end end: wsh:= p-> n-> weigh(p)(n-1): a:= (wsh@@2)(n-> `if`(n>0 and n<12, [1$3, 2$5, 1$3][n], 0)): seq(a(n), n=1..50); # _Alois P. Heinz_, Sep 10 2008

%t Nest[CoefficientList[Series[Product[(1+x^i)^#[[i]],{i,1,Length[#]}],{x,0,40}],x]&,{1},5] (* _Geoffrey Critzer_, Aug 01 2013 *)

%Y Cf. A038081-A038093.

%K nonn,fini

%O 1,4

%A _Christian G. Bower_, Jan 04 1999.

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified November 27 12:15 EST 2015. Contains 264547 sequences.