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A320217
Number of multisets of nonempty words with a total of n letters over septenary alphabet such that all letters occur at least once in the multiset.
3
37633, 1394414, 30044014, 493609088, 6864854521, 85265606888, 976232236182, 10515038040403, 108038163343516, 1069407324384749, 10272179741315583, 96275040557582796, 884152621318502522, 7982464409593829883, 71036604818774830215, 624423552992566806913
OFFSET
7,1
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))(7):
seq(a(n), n=7..25);
CROSSREFS
Column k=7 of A257740.
Cf. A320208.
Sequence in context: A092682 A236122 A320208 * A236883 A048526 A190320
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Oct 07 2018
STATUS
approved