A293115 Number of sets of nonempty words with a total of 2n letters over n-ary alphabet containing the n-th letter such that within each prefix of a word every letter of the alphabet is at least as frequent as the subsequent alphabet letter.

1, 1, 8, 53, 410, 3576, 35878, 391136, 4666521, 59096165, 797628339, 11282268353, 167582833398, 2587994886476, 41585338511800, 690912445945576, 11870082701946292, 209995330141487944, 3824511903396303251, 71496027436457015058, 1371314535020854180410

Offset

0,3

Links

Alois P. Heinz, Table of n, a(n) for n = 0..26

Formula

a(n) = A293113(2n,n).

Crossrefs

Cf. A182172, A293111, A293113.

Sequence in context: A091870 A252824 A054418 * A337554 A370359 A070928

Adjacent sequences: A293112 A293113 A293114 * A293116 A293117 A293118

Keyword

nonn

Author

Alois P. Heinz, Sep 30 2017

Status

approved