A351639 Number of length n word structures with all distinct run-lengths using at most 3 symbols.

1, 1, 1, 3, 3, 5, 17, 19, 31, 45, 153, 167, 287, 397, 613, 1695, 2007, 3185, 4565, 6799, 9235, 24057, 27645, 44483, 61619, 92089, 122857, 179355, 385995, 468605, 713849, 996331, 1441447, 1947813, 2766657, 3659135, 7467623, 8930629, 13471885, 18283575, 26484639

Offset: 0

Author

Andrew Howroyd, Feb 15 2022

Keywords

• nonn

Links

• Andrew Howroyd, Table of n, a(n) for n = 0..1000

Crossrefs

Column k=3 of A351637.

Cf. A351638.

Programs

PARI

\\ See A351637 for P, R.
seq(n)={my(u=P(n)); concat([1], sum(k=1, n, R(u, k)*sum(r=k, 3, binomial(r, k)*(-1)^(r-k)/r!) ))}