A268870 Number of sequences in {1,...,n}^n with longest increasing subsequence of length three.

1, 45, 1131, 23611, 461154, 8837823, 169844455, 3307239364, 65559881608, 1325285983528, 27321430823064, 573932303529170, 12269791047231748, 266575464412874571, 5877527995117635663, 131334452330324176828, 2970563969803965041900, 67935408457473145627500

Offset

3,2

Links

Alois P. Heinz, Table of n, a(n) for n = 3..700

Formula

a(n) = A239299(n) - A239295(n).

Example

a(3) = 1: 123.
a(4) = 45: 1123, 1124, 1134, 1213, 1214, 1223, 1224, 1231, 1232, 1233, 1241, 1242, 1243, 1244, 1314, 1323, 1324, 1334, 1341, 1342, 1343, 1344, 1423, 1424, 1434, 2123, 2124, 2134, 2234, 2314, 2324, 2334, 2341, 2342, 2343, 2344, 2434, 3123, 3124, 3134, 3234, 4123, 4124, 4134, 4234.

Crossrefs

Column k=3 of A245667.

Cf. A239295, A239299.

Sequence in context: A265615 A320363 A140346 * A049447 A327510 A215769

Adjacent sequences: A268867 A268868 A268869 * A268871 A268872 A268873

Keyword

nonn,easy

Author

Alois P. Heinz, Feb 15 2016

Status

approved