|
Search: id:A141770
|
|
|
| A141770 |
|
Number of recursively combed cube orientations. |
|
+0
1
|
|
| 1, 2, 12, 680, 3209712, 94504354122272, 100812007252263643279948656576, 135585824090362207213177704090990942335416773530694383100032, 28257086726657883005841592086461399679973344564503337667169873458565649006970772\ 0544980164859900048942541095947330649856
(list; graph; listen)
|
|
|
OFFSET
|
0,2
|
|
|
COMMENT
|
An orientation of the edges of the d-dimensional hypercube is recursively combed if there is at least one dimension along which all the edges go into the same direction and the two (d-1)-dimensional cube orientations resulting from the removal of all edges along that dimension are again recursively combed.
|
|
REFERENCES
|
GWOP 2008, 6th Gremo Workshop on Open Problems
|
|
FORMULA
|
f(n) = sum((-1)^(j+1)*2^j*binomial(n,j)*f(n-j)^(2^j), j=1..n), f(0) = 1
|
|
MAPLE
|
f[0] := 1; for k from 1 to 8 do f[k] := sum((-1)^(j+1)*2^j*binomial(k, j)*f[k-j]^(2^j), j=1..k); od;
|
|
CROSSREFS
|
Sequence in context: A002860 A108078 A052129 this_sequence A060055 A061149 A129933
Adjacent sequences: A141767 A141768 A141769 this_sequence A141771 A141772 A141773
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Philipp Zumstein (zuphilip(AT)inf.ethz.ch), Sep 16 2008
|
|
|
Search completed in 0.002 seconds
|
