A293884 Number of sets of nonempty words with a total of n letters over ternary alphabet containing the third 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, 4, 16, 53, 173, 532, 1615, 4785, 14066, 40908, 118438, 341253, 981200, 2815762, 8075265, 23149097, 66373778, 190376443, 546401592, 1569387414, 4511532695, 12980998062, 37385342522, 107771434819, 310967929569, 898108427259, 2596180252466, 7511411442182

Offset

3,2

Links

Alois P. Heinz, Table of n, a(n) for n = 3..1000

Formula

a(n) = A293742(n) - A293741(n).

Crossrefs

Column k=3 of A293113.

Cf. A293741, A293742.

Sequence in context: A056589 A074407 A192074 * A121159 A358232 A239032

Adjacent sequences: A293881 A293882 A293883 * A293885 A293886 A293887

Keyword

nonn

Author

Alois P. Heinz, Oct 18 2017

Status

approved