|
| |
|
|
A052540
|
|
Expansion of (1-x)/(1-2x-x^3+x^4).
|
|
1
| |
|
|
1, 1, 2, 5, 10, 21, 45, 95, 201, 426, 902, 1910, 4045, 8566, 18140, 38415, 81351, 172276, 364827, 772590, 1636105, 3464761, 7337285, 15538085, 32904826, 69682176, 147565152, 312497045, 661771440, 1401425856, 2967783605
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,3
|
|
|
COMMENTS
| Equals INVERT transform of (1, 1, 2, 1, 1, 1,...). [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Apr 27 2009]
|
|
|
LINKS
| INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 472
Index to sequences with linear recurrences with constant coefficients, signature (2,0,1,-1).
|
|
|
FORMULA
| G.f.: -(-1+x)/(1-2*x-x^3+x^4)
Recurrence: {a(1)=1, a(0)=1, a(3)=5, a(2)=2, a(n)-a(n+1)-2*a(n+3)+a(n+4)}
Sum(-1/643*(-94-127*_alpha-22*_alpha^2+75*_alpha^3)*_alpha^(-1-n), _alpha=RootOf(1-2*_Z-_Z^3+_Z^4))
|
|
|
MAPLE
| spec := [S, {S=Sequence(Prod(Z, Union(Prod(Z, Z), Sequence(Z))))}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);
|
|
|
CROSSREFS
| Sequence in context: A114279 A101400 A131403 * A018106 A192317 A151497
Adjacent sequences: A052537 A052538 A052539 * A052541 A052542 A052543
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| encyclopedia(AT)pommard.inria.fr, Jan 25 2000
|
|
|
EXTENSIONS
| More terms from James A. Sellers (sellersj(AT)math.psu.edu), Jun 05 2000
|
| |
|
|
