|
|
A256096
|
|
Expansion of (4+3*x)/(1+3*x).
|
|
2
|
|
|
4, -9, 27, -81, 243, -729, 2187, -6561, 19683, -59049, 177147, -531441, 1594323, -4782969, 14348907, -43046721, 129140163, -387420489, 1162261467, -3486784401, 10460353203, -31381059609, 94143178827, -282429536481, 847288609443, -2541865828329, 7625597484987
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,1
|
|
COMMENTS
|
This is the Z-sequence of the Riordan triangle ((1+2*x)/(1-x)^2, x/(1-x)). See A135857.
The expansion can be seen as a special case of the family of generating functions 1+1/(x+1/k) for k>=1 which relates this sequence to A054977 and A198633 (neglecting questions of sign). - Peter Luschny, Mar 24 2015
|
|
LINKS
|
|
|
FORMULA
|
O.g.f.: (4+3*x)/(1+3*x).
a(0) = 4; for n >= 1, a(n) = (-1)^n*3^(n+1).
a(0) = 4, a(1) = -9; for n >= 2, a(n) = -3*a(n-1).
|
|
MATHEMATICA
|
|
|
PROG
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
sign,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|