A228621 Number of s in {1,...,n}^n having shortest run with the same value of length 2.

2, 0, 12, 40, 210, 840, 5208, 23760, 148410, 786720, 5137440, 30051528, 207058488, 1318599240, 9540828480, 65319695136, 495194683680, 3608366801040, 28572937581140, 219952629498840, 1813839842408748, 14663194937503288, 125593649761912704, 1061139859894326000

Offset: 2

Author

Alois P. Heinz, Aug 28 2013

Keywords

• nonn

Examples

			a(2) = 2: [1,1], [2,2].
a(4) = 12: [1,1,2,2], [1,1,3,3], [1,1,4,4], [2,2,1,1], [2,2,3,3], [2,2,4,4], [3,3,1,1], [3,3,2,2], [3,3,4,4], [4,4,1,1], [4,4,2,2], [4,4,3,3].
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 2..180

Crossrefs

Column k=2 of A228617.