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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.
2
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
FORMULA
a(n) = A293742(n) - A293741(n).
CROSSREFS
Column k=3 of A293113.
Sequence in context: A056589 A074407 A192074 * A121159 A358232 A239032
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Oct 18 2017
STATUS
approved