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A211283 a(n) = number of n-lettered words in the alphabet {1, 2, 3} with as many occurrences of the substring (consecutive subword) [1, 1, 1] as of [1, 2, 1]. 1
1, 3, 9, 25, 70, 200, 569, 1614, 4596, 13114, 37431, 106978, 306238, 877713, 2518647, 7236947, 20820856, 59975554, 172974739, 499480558, 1444006498, 4179496707, 12110820951, 35132286213, 102025868324, 296601381043, 863142552053, 2514348427139, 7331433782002, 21397338280852, 62506435095245 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
Shalosh B. Ekhad and Doron Zeilberger, Automatic Solution of Richard Stanley's Amer. Math. Monthly Problem #11610 and ANY Problem of That Type, arXiv preprint arXiv:1112.6207, 2011. See subpages for rigorous derivations of g.f., recurrence, asymptotics for this sequence.
CROSSREFS
Sequence in context: A333498 A097861 A211284 * A333608 A058719 A046661
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Apr 07 2012
STATUS
approved

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Last modified March 29 08:51 EDT 2024. Contains 371268 sequences. (Running on oeis4.)