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A034854 Triangle giving number of rooted labeled trees with n >= 3 nodes and diameter d>=2. 1
3, 4, 12, 5, 60, 60, 6, 210, 720, 360, 7, 630, 6090, 7560, 2520, 8, 1736, 47040, 112560, 80640, 20160, 9, 4536, 363384, 1496880, 1829520, 907200, 181440, 10, 11430, 2913120, 19207440, 36892800, 28274400, 10886400, 1814400 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..35.

J. Riordan, Enumeration of trees by height and diameter, IBM J. Res. Dev. 4 (1960), 473-478.[broken link]

J. Riordan, Enumeration of trees by height and diameter, IBM J. Res. Dev. 4 (1960), 473-478.

J. Riordan, The enumeration of trees by height and diameter, IBM Journal 4 (1960), 473-478. (Annotated scanned copy)

Index entries for sequences related to trees

FORMULA

Reference gives recurrence.

EXAMPLE

Triangle begins:

3;

4 12;

5 60 60;

6 210 720 360;

7 630 6090 7560 2520;

..

CROSSREFS

Cf. A001852, A034855.

Sequence in context: A084200 A097850 A238855 * A164982 A081837 A196440

Adjacent sequences:  A034851 A034852 A034853 * A034855 A034856 A034857

KEYWORD

nonn,tabl,easy,nice

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Pab Ter (pabrlos(AT)yahoo.com), May 27 2004

STATUS

approved

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Last modified November 15 11:35 EST 2018. Contains 317238 sequences. (Running on oeis4.)