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A262197
Number of compositions of n such that the maximal distance between two identical parts equals four.
1
0, 1, 3, 9, 21, 46, 92, 180, 330, 595, 1039, 1793, 3023, 5030, 8248, 13388, 21518, 34231, 54079, 84607, 131603, 203050, 311738, 474974, 720666, 1086125, 1629815, 2431647, 3612665, 5339710, 7860366, 11519856, 16816312, 24448029, 35409609
OFFSET
4,3
EXAMPLE
a(5) = 1: 11111.
a(6) = 3: 11121, 11211, 12111.
a(7) = 9: 11131, 11221, 11311, 12121, 12211, 13111, 21112, 111112, 211111.
a(8) = 21: 11141, 11231, 11321, 11411, 12131, 12221, 12311, 13121, 13211, 14111, 21122, 21212, 22112, 111113, 111212, 112112, 121112, 211121, 211211, 212111, 311111.
CROSSREFS
Column k=4 of A262191.
Sequence in context: A063830 A062444 A141156 * A014286 A000714 A267226
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 14 2015
STATUS
approved