|
|
A052563
|
|
E.g.f.: (1-x)/(1-3*x).
|
|
3
|
|
|
1, 2, 12, 108, 1296, 19440, 349920, 7348320, 176359680, 4761711360, 142851340800, 4714094246400, 169707392870400, 6618588321945600, 277980709521715200, 12509131928477184000, 600438332566904832000
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
COMMENTS
|
|
|
LINKS
|
|
|
FORMULA
|
E.g.f.: (-1+x)/(-1+3*x)
Recurrence: {a(0)=1, a(1)=2, (-3*n-3)*a(n)+a(n+1)=0}
a(n) = 2*3^(n-1)*n!.
|
|
MAPLE
|
spec := [S, {S=Sequence(Prod(Union(Z, Z), Sequence(Z)))}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
|
|
MATHEMATICA
|
With[{nn=20}, CoefficientList[Series[(1-x)/(1-3x), {x, 0, nn}], x] Range[ 0, nn]!] (* Harvey P. Dale, May 21 2014 *)
|
|
PROG
|
(PARI) x='x+O('x^30); Vec(serlaplace((1-x)/(1-3*x))) \\ G. C. Greubel, May 23 2018
(Magma) m:=25; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!((1-x)/(1-3*x))); [Factorial(n-1)*b[n]: n in [1..m]]; // G. C. Greubel, May 23 2018
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
encyclopedia(AT)pommard.inria.fr, Jan 25 2000
|
|
STATUS
|
approved
|
|
|
|