login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A259100 Triangle read by rows, arising in the enumeration of corners. 1
1, 0, 1, 0, 2, 1, 0, 3, 2, 1, 0, 4, 5, 2, 1, 0, 5, 8, 5, 2, 1, 0, 6, 14, 10, 5, 2, 1, 0, 7, 20, 18, 10, 5, 2, 1, 0, 8, 30, 30, 20, 10, 5, 2, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Table of n, a(n) for n=0..44.

G. Kreweras, Sur les extensions linéaires d'une famille particuliere d'ordres partiels, Discrete Math., 27 (1979), 279-295.

G. Kreweras, Sur les extensions linéaires d'une famille particulière d'ordres partiels, Discrete Math., 27 (1979), 279-295. (Annotated scanned copy)

FORMULA

Kreweras gives a recurrence on page 281.

EXAMPLE

Triangle begins:

  1;

  0,  1;

  0,  2,  1;

  0,  3,  2,  1;

  0,  4,  5,  2,  1;

  0,  5,  8,  5,  2,  1;

  0,  6, 14, 10,  5,  2,  1;

  0,  7, 20, 18, 10,  5,  2,  1;

  0,  8, 30, 30, 20, 10,  5,  2,  1;

  ...

CROSSREFS

Row sums = A006330.

Sequence in context: A025653 A131103 A180653 * A096652 A322133 A274183

Adjacent sequences:  A259097 A259098 A259099 * A259101 A259102 A259103

KEYWORD

nonn,tabl,more

AUTHOR

N. J. A. Sloane, Jun 22 2015

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 January 22 07:39 EST 2020. Contains 331139 sequences. (Running on oeis4.)