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A214267 Central column of the Seidel-Entringer triangles A008281 and A008282. 2
1, 1, 1, 2, 4, 14, 46, 224, 1024, 6320, 36976, 275792, 1965664, 17180144, 144361456, 1446351104, 13997185024, 158116017920, 1731678144256, 21771730437632, 266182076161024, 3686171162253824, 49763143319190016, 752594181757712384, 11118629668610842624 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

a(n) takes alternatingly the values of the central column of the Seidel-Entriger triangles A008281 (1,1,4,46,...) and A008282 (1,2,14,224,..).

In Gelineau, Shin, and Zeng (section 6.1) twelve interpretations of the numbers can be found.

LINKS

Table of n, a(n) for n=0..24.

Yoann Gelineau, Heesung Shin and Jiang Zeng, Bijections for Entringer families.

MAPLE

A214267 := proc(n) local S; S := proc(n, k) option remember; if k=0 then `if`(n=0, 1, 0) else S(n, k-1)+S(n-1, n-k) fi end: S(n, iquo(n+1, 2)) end; seq(A214267(i), i=0..24);

CROSSREFS

Sequence in context: A149851 A149852 A005437 * A062868 A054936 A006443

Adjacent sequences:  A214264 A214265 A214266 * A214268 A214269 A214270

KEYWORD

nonn

AUTHOR

Peter Luschny, Jul 09 2012

STATUS

approved

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Last modified October 1 04:35 EDT 2014. Contains 247500 sequences.