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A007560 Number of planted identity trees where non-root, non-leaf nodes an even distance from root are of degree 2.
(Formerly M0325)
+0
1
1, 1, 1, 1, 2, 2, 4, 6, 10, 17, 29, 51, 89, 159, 284, 512, 930, 1692, 3101, 5698, 10515, 19464, 36143, 67296, 125622, 235050, 440756, 828142, 1558955, 2939761, 5552744, 10504222, 19899760, 37750091, 71704061 (list; graph; listen)
OFFSET

1,5

LINKS

M. Bernstein and N. J. A. Sloane, Some canonical sequences of integers, Linear Alg. Applications, 226-228 (1995), 57-72; erratum 320 (2000), 210.

N. J. A. Sloane, Transforms

Index entries for sequences related to rooted trees

FORMULA

Shifts 2 places left under weigh transform.

CROSSREFS

Sequence in context: A000016 A060553 A032307 this_sequence A032237 A124346 A033961

Adjacent sequences: A007557 A007558 A007559 this_sequence A007561 A007562 A007563

KEYWORD

nonn,nice,eigen

AUTHOR

njas.

EXTENSIONS

Better description from Christian G. Bower (bowerc(AT)usa.net), May 15 1998.

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Last modified July 25 07:41 EDT 2008. Contains 142293 sequences.


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