|
|
A135704
|
|
a(n) = 7*n^2 + 4*n + 1.
|
|
2
|
|
|
4, 1, 12, 37, 76, 129, 196, 277, 372, 481, 604, 741, 892, 1057, 1236, 1429, 1636, 1857, 2092, 2341, 2604, 2881, 3172, 3477, 3796, 4129, 4476, 4837, 5212, 5601, 6004, 6421, 6852, 7297, 7756, 8229, 8716, 9217, 9732, 10261, 10804, 11361, 11932
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
-1,1
|
|
LINKS
|
|
|
FORMULA
|
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3).
G.f.: (4 - 11*x + 21*x^2)/(x * (1 - x)^3).
E.g.f.: 4/x + (1 + 11*x + 7*x^2)*exp(x). (End)
|
|
MATHEMATICA
|
LinearRecurrence[{3, -3, 1}, {4, 1, 12}, 25] (* G. C. Greubel, Oct 29 2016 *)
|
|
PROG
|
|
|
CROSSREFS
|
This is simply A005892 with offset -1.
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|