A262197 Number of compositions of n such that the maximal distance between two identical parts equals four.

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

Author

Alois P. Heinz, Sep 14 2015

Keywords

• nonn

Examples

			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.