|
| |
|
|
A245860
|
|
Number of preferential arrangements of n labeled elements such that the minimal number of elements per rank equals 7.
|
|
2
|
|
|
|
1, 0, 0, 0, 0, 0, 0, 3432, 12870, 22880, 38896, 63648, 100776, 155040, 399305520, 3292693008, 17879790324, 70676513424, 242216077400, 762341522800, 2264840592300, 478970960616720, 6869326015894680, 61426122596911800, 435982960069722000, 2589856033041531072
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
7,8
|
|
|
LINKS
|
Alois P. Heinz, Table of n, a(n) for n = 7..400
|
|
|
FORMULA
|
E.g.f.: 1/(1-Sum_{j>=7} x^j/j!) - 1/(1-Sum_{j>=8} x^j/j!).
a(n) = A245792(n) - A245793(n) = A245732(n,7) - A245732(n,8).
|
|
|
MAPLE
|
b:= proc(n, k) option remember; `if`(n=0, 1,
add(b(n-j, k)*binomial(n, j), j=k..n))
end:
a:= n-> b(n, 7) -b(n, 8):
seq(a(n), n=7..35);
|
|
|
CROSSREFS
|
Column k=7 of A245733.
Cf. A245792, A245793, A245732.
Sequence in context: A290290 A024751 A024759 * A177307 A140911 A351486
Adjacent sequences: A245857 A245858 A245859 * A245861 A245862 A245863
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Alois P. Heinz, Aug 04 2014
|
|
|
STATUS
|
approved
|
| |
|
|
