|
| |
| |
|
|
|
0, 6, 54, 324, 1620, 7290, 30618, 122472, 472392, 1771470, 6495390, 23383404, 82904796, 290166786, 1004423490, 3443737680, 11708708112, 39516889878, 132497807238, 441659357460, 1464449448420, 4832683179786, 15878816162154
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,2
|
|
|
LINKS
|
Vincenzo Librandi, Table of n, a(n) for n = 0..1000
Index to sequences with linear recurrences with constant coefficients, signature (9,-27,27).
|
|
|
FORMULA
|
G.f.: 6*x/(1-3*x)^3. a(n)=6*A027472(n+2). - R. J. Mathar, Dec 19 2008
a(n) = 9*a(n-1)-27*a(n-2)+27*a(n-3). - Vincenzo Librandi, Feb 28 2013
|
|
|
MATHEMATICA
|
Table[(n^2 + n) 3^n, {n, 0, 30}] (* Vincenzo Librandi, Feb 28 2013 *)
|
|
|
PROG
|
(MAGMA) [(n^2+n)*3^n: n in [0..25]]; /* or */ I:=[0, 6, 54]; [n le 3 select I[n] else 9*Self(n-1)-27*Self(n-2)+27*Self(n-3): n in [1..30]]; // Vincenzo Librandi, Feb 28 2013
(PARI) a(n)=(n^2+n)*3^n \\ Charles R Greathouse IV, Feb 28 2013
|
|
|
CROSSREFS
|
Cf. A007758, A036289, A128796, A027472.
Sequence in context: A153333 A195901 A072368 * A060774 A043026 A125837
Adjacent sequences: A116135 A116136 A116137 * A116139 A116140 A116141
|
|
|
KEYWORD
|
nonn,easy
|
|
|
AUTHOR
|
Mohammad K. Azarian, Apr 08 2007
|
|
|
STATUS
|
approved
|
| |
|
|
