|
|
A275874
|
|
a(n) = (n-4)*(n+1)*(n+3)/6.
|
|
4
|
|
|
0, 8, 21, 40, 66, 100, 143, 196, 260, 336, 425, 528, 646, 780, 931, 1100, 1288, 1496, 1725, 1976, 2250, 2548, 2871, 3220, 3596, 4000, 4433, 4896, 5390, 5916, 6475, 7068, 7696, 8360, 9061, 9800, 10578, 11396, 12255, 13156, 14100, 15088, 16121, 17200, 18326, 19500, 20723, 21996
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
4,2
|
|
LINKS
|
|
|
FORMULA
|
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n > 7.
G.f.: x^5*(8 - 11*x + 4*x^2) / (1 - x)^4.
(End)
|
|
MAPLE
|
a := n -> (n - 4)*(n + 1)*(n + 3)/6:
|
|
PROG
|
(PARI) concat(0, Vec(x^5*(8-11*x+4*x^2)/(1-x)^4 + O(x^50))) \\ Colin Barker, Aug 15 2016
|
|
CROSSREFS
|
A137742 is an essentially identical sequence.
|
|
KEYWORD
|
nonn,easy
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|