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.

73, 1028, 9182, 66584, 428653, 2557972, 14496714, 79179724, 420817947, 2190356332, 11216217292, 56689332604, 283477764373, 1404999644584, 6911375241384, 33778491898132, 164157640596783, 793799200891568, 3821351207383146, 18321693995577480, 87520485093330489

Offset

4,1

Links

Alois P. Heinz, Table of n, a(n) for n = 4..1000

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

Column k=4 of A257740.

Cf. A320205.

Sequence in context: A057522 A320205 A305549 * A346642 A008400 A090685

Adjacent sequences: A320211 A320212 A320213 * A320215 A320216 A320217

Keyword

nonn

Author

Alois P. Heinz, Oct 07 2018

Status

approved