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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A134772 Let f(M,N)=2^(-M)*sum_{i=0..N} {(-1)^{i}M!N!(2M-2i)!}/{i!(M-i)!(N-i)!6^{N-i}}; then a(n) = f(2n,n). 4
1, 0, 28, 14400, 27165600, 134289792000, 1445549490000000, 29865588836219136000, 1081114481157129619200000, 64007711015400701105356800000, 5873237165016878140678626432000000, 799901135455942846519287494400000000000, 156064894765355001368149078831725782016000000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..12.

CROSSREFS

A variant of A132202. Bisections: A137942, A144649. Cf. A134648, A152296.

Sequence in context: A221691 A159415 A209177 * A085408 A159419 A147291

Adjacent sequences:  A134769 A134770 A134771 * A134773 A134774 A134775

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Oct 18 2009

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 September 20 22:20 EDT 2019. Contains 327252 sequences. (Running on oeis4.)