|
| |
|
|
A162258
|
|
(2n^3+5n^2-9n)/2.
|
|
1
|
|
|
|
-1, 9, 36, 86, 165, 279, 434, 636, 891, 1205, 1584, 2034, 2561, 3171, 3870, 4664, 5559, 6561, 7676, 8910, 10269, 11759, 13386, 15156, 17075, 19149, 21384, 23786, 26361, 29115, 32054, 35184, 38511, 42041, 45780, 49734, 53909, 58311, 62946, 67820
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,2
|
|
|
LINKS
|
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
Index to sequences with linear recurrences with constant coefficients, signature (4, -6, 4, -1).
|
|
|
FORMULA
|
Row sums from A155546: a(n) = sum(2*m*n+m+n-5, m=1..n).
G.f.: x*(-1+13*x-6*x^2)/(1-x)^4. - Vincenzo Librandi, Mar 04 2012
a(n) = 4*a(n-1) -6*a(n-2) +4*a(n-3) -a(n-4). - Vincenzo Librandi, Mar 04 2012
|
|
|
MATHEMATICA
|
LinearRecurrence[{4, -6, 4, -1}, {-1, 9, 36, 86}, 50] (* or *) CoefficientList[Series[(2+7*x-3*x^2)/(1-x)^4, {x, 0, 50}], x] (* Vincenzo Librandi, Mar 04 2012 *)
|
|
|
CROSSREFS
|
Cf. A155546.
Sequence in context: A009522 A045851 A173243 * A128642 A022604 A085630
Adjacent sequences: A162255 A162256 A162257 * A162259 A162260 A162261
|
|
|
KEYWORD
|
sign,easy
|
|
|
AUTHOR
|
Vincenzo Librandi, Jun 29 2009
|
|
|
EXTENSIONS
|
New name from Vincenzo Librandi, Mar 04 2012
|
|
|
STATUS
|
approved
|
| |
|
|
