login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A137512 The number of nodes visible from underneath a binary tree, where the nodes are placed such that the innermost of the two sprouting nodes should be underneath the mother. 0
1, 1, 2, 3, 3, 3, 4, 5, 5, 6, 6, 6, 7, 7, 8, 9, 9, 10, 10, 11, 11, 12, 12, 12, 13, 13, 14, 14, 15, 15, 16 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..31.

EXAMPLE

For n=12:

.....0..

.....00.

...0.000

..00000.

we can see nodes 7,8,9,10,11,12 ==> a(12) = 6

CROSSREFS

Sequence in context: A137580 A196369 A245710 * A157943 A267098 A304110

Adjacent sequences:  A137509 A137510 A137511 * A137513 A137514 A137515

KEYWORD

nonn

AUTHOR

David Reiss (david.reiss(AT)utoronto.ca), May 11 2008

EXTENSIONS

I think I managed to destroy the example by editing it. - N. J. A. Sloane, May 16 2008

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 18 13:31 EDT 2019. Contains 328161 sequences. (Running on oeis4.)