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

2,1

Links

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

Example

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].

Crossrefs

Column k=2 of A228617.

Sequence in context: A112261 A134831 A074001 * A180189 A182437 A326860

Adjacent sequences: A228618 A228619 A228620 * A228622 A228623 A228624

Keyword

nonn

Author

Alois P. Heinz, Aug 28 2013

Status

approved