|
| |
|
|
A322536
|
|
Number of arrays of 9 integers in -n..n with sum zero.
|
|
2
|
|
|
|
1, 3139, 180325, 2636263, 19610233, 97464799, 370487485, 1163205475, 3164588407, 7702189345, 17148949027, 35500063501, 69161990275, 128000343121, 226698100687, 386480229085, 637265493637, 1020310909975, 1591418959705, 2424782370859, 3617545938373, 5295169534843
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
0,2
|
|
|
LINKS
|
Seiichi Manyama, Table of n, a(n) for n = 0..10000
|
|
|
FORMULA
|
a(n) = [x^(9*n)] (Sum_{k=0..2*n} x^k)^9.
|
|
|
MATHEMATICA
|
a[n_] := Coefficient[Expand[Sum[x^k, {k, 0, 2n}]^9, x], x, 9n]; Array[a, 25, 0] (* Amiram Eldar, Dec 14 2018 *)
|
|
|
PROG
|
(PARI) {a(n) = polcoeff((sum(k=0, 2*n, x^k))^9, 9*n, x)}
|
|
|
CROSSREFS
|
Row 9 of A201552.
Sequence in context: A187645 A187640 A187639 * A172641 A172744 A172819
Adjacent sequences: A322533 A322534 A322535 * A322537 A322538 A322539
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Seiichi Manyama, Dec 14 2018
|
|
|
STATUS
|
approved
|
| |
|
|
