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A239375
Number of words of length n over the alphabet {0, ..., n-1} that avoid the pattern 1221.
0
1, 1, 4, 27, 250, 2915, 40766, 662494, 12236190, 252664815, 5759288044, 143463453199, 3873471153366, 112587628893480
OFFSET
0,3
CROSSREFS
Cf. A239295.
Sequence in context: A000699 A138423 A239372 * A239370 A239369 A246526
KEYWORD
nonn,more
AUTHOR
Chad Brewbaker, Mar 17 2014
EXTENSIONS
a(8)-a(13) from Martin Ehrenstein, Dec 03 2023
STATUS
approved