|
| |
|
|
A211387
|
|
Expansion of x*(1 -15*x +99*x^2 -373*x^3 +879*x^4 -1338*x^5 +1311*x^6 -804*x^7 +289*x^8 -44*x^9) / [(1-3*x+x^2) *(1-2*x)^6 *(1-x)^2].
|
|
0
|
|
|
|
1, 2, 5, 17, 69, 286, 1137, 4277, 15247, 51786, 168566, 528740, 1606023, 4744071, 13678697, 38620692, 107073080, 292195582, 786536753, 2092318473, 5509620835, 14382935710, 37272512506, 96000674264, 246029006363, 628007115019, 1598123382173, 4057780889704
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,2
|
|
|
COMMENTS
|
Appears in the enumeration of {1324,4312}-avoiding permutations. [Albert et al., Section 5.7]
|
|
|
LINKS
|
Index entries for linear recurrences with constant coefficients, signature (17,-128,561,-1581,2984,-3804,3216,-1712,512,-64).
|
|
|
FORMULA
|
a(n) = -21 -5*n +2^n*(267/16 +n^4/128 -161*n^3/768 +229*n^2/128 -451*n/40 +n^5/3840) +A001519(n+3).
|
|
|
CROSSREFS
|
|
|
|
KEYWORD
|
nonn,easy
|
|
|
AUTHOR
|
|
|
|
STATUS
|
approved
|
| |
|
|
