|
| |
|
|
A167715
|
|
Number of reduced words of length n in Coxeter group on 30 generators S_i with relations (S_i)^2 = (S_i S_j)^15 = I.
|
|
0
|
|
|
|
1, 30, 870, 25230, 731670, 21218430, 615334470, 17844699630, 517496289270, 15007392388830, 435214379276070, 12621216999006030, 366015292971174870, 10614443496164071230, 307818861388758065670, 8926746980273983903995
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,2
|
|
|
COMMENTS
|
The initial terms coincide with those of A170749, although the two sequences are eventually different.
Computed with MAGMA using commands similar to those used to compute A154638.
|
|
|
LINKS
|
Table of n, a(n) for n=0..15.
|
|
|
FORMULA
|
G.f. (t^15 + 2*t^14 + 2*t^13 + 2*t^12 + 2*t^11 + 2*t^10 + 2*t^9 + 2*t^8 + 2*t^7 +
2*t^6 + 2*t^5 + 2*t^4 + 2*t^3 + 2*t^2 + 2*t + 1)/(406*t^15 - 28*t^14 -
28*t^13 - 28*t^12 - 28*t^11 - 28*t^10 - 28*t^9 - 28*t^8 - 28*t^7 -
28*t^6 - 28*t^5 - 28*t^4 - 28*t^3 - 28*t^2 - 28*t + 1)
|
|
|
CROSSREFS
|
Sequence in context: A166617 A167083 A167370 * A167945 A168707 A168755
Adjacent sequences: A167712 A167713 A167714 * A167716 A167717 A167718
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
John Cannon (john(AT)maths.usyd.edu.au) and N. J. A. Sloane, Dec 03 2009
|
|
|
STATUS
|
approved
|
| |
|
|
