|
|
A320214
|
|
Number of multisets of nonempty words with a total of n letters over quaternary alphabet such that all letters occur at least once in the multiset.
|
|
3
|
|
|
73, 1028, 9182, 66584, 428653, 2557972, 14496714, 79179724, 420817947, 2190356332, 11216217292, 56689332604, 283477764373, 1404999644584, 6911375241384, 33778491898132, 164157640596783, 793799200891568, 3821351207383146, 18321693995577480, 87520485093330489
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
4,1
|
|
LINKS
|
|
|
MAPLE
|
b:= proc(n, k) option remember; `if`(n=0, 1, add(add(
d*k^d, d=numtheory[divisors](j))*b(n-j, k), j=1..n)/n)
end:
a:= n-> (k-> add(b(n, k-i)*(-1)^i*binomial(k, i), i=0..k))(4):
seq(a(n), n=4..25);
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|