A320213 Number of multisets of nonempty words with a total of n letters over ternary alphabet such that all letters occur at least once in the multiset.

13, 114, 672, 3334, 15030, 63978, 261880, 1043658, 4076856, 15688108, 59650623, 224625639, 839026657, 3112293273, 11474908920, 42080197859, 153566261268, 557943898644, 2018901838589, 7277784002970, 26142839723154, 93599166705077, 334072869753357

Offset

3,1

Links

Alois P. Heinz, Table of n, a(n) for n = 3..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))(3):
seq(a(n), n=3..30);

Crossrefs

Column k=3 of A257740.

Cf. A320204.

Sequence in context: A254038 A221369 A095680 * A323037 A320617 A156969

Adjacent sequences: A320210 A320211 A320212 * A320214 A320215 A320216

Keyword

nonn

Author

Alois P. Heinz, Oct 07 2018

Status

approved