|
|
A155485
|
|
a(n) = 5^n + (1 - 4^n)/3.
|
|
1
|
|
|
1, 4, 20, 104, 540, 2784, 14260, 72664, 368780, 1865744, 9416100, 47430024, 238548220, 1198333504, 6014037140, 30159664184, 151156234860, 757212830064, 3791790773380, 18981860359144, 95000927764700, 475371142699424, 2378321729000820, 11897472707018904
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
LINKS
|
|
|
FORMULA
|
a(n) = 10a(n-1) - 29a(n-2) + 20a(n-3), as in A097165.
G.f.: (1-3x)^2/((1-x)(1-4x)(1-5x)).
|
|
PROG
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
EXTENSIONS
|
Edited, Lava definition adopted, and extended by R. J. Mathar, Feb 27 2009
|
|
STATUS
|
approved
|
|
|
|