A267479 Number A(n,k) of words on {1,1,2,2,...,n,n} with longest increasing subsequence of length <= k; square array A(n,k), n>=0, k>=0, read by antidiagonals.

1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 6, 1, 0, 1, 1, 6, 43, 1, 0, 1, 1, 6, 90, 352, 1, 0, 1, 1, 6, 90, 1879, 3114, 1, 0, 1, 1, 6, 90, 2520, 47024, 29004, 1, 0, 1, 1, 6, 90, 2520, 102011, 1331664, 280221, 1, 0, 1, 1, 6, 90, 2520, 113400, 5176504, 41250519, 2782476, 1, 0

Offset

0,13

Links

Alois P. Heinz, Antidiagonals n = 0..30, flattened

Ferenc Balogh, A generalization of Gessel's generating function to enumerate words with double or triple occurrences in each letter and without increasing subsequences of a given length, arXiv:1505.01389, 2015

Shalosh B. Ekhad and Doron Zeilberger, The Generating Functions Enumerating 12..d-Avoiding Words with r occurrences of each of 1,2, ..., n are D-finite for all d and all r, 2014

Formula

A(n,k) = Sum_{i=0..k} A267480(n,i).

Example

Square array A(n,k) begins:
  1, 1,     1,       1,       1,       1,       1, ...
  0, 1,     1,       1,       1,       1,       1, ...
  0, 1,     6,       6,       6,       6,       6, ...
  0, 1,    43,      90,      90,      90,      90, ...
  0, 1,   352,    1879,    2520,    2520,    2520, ...
  0, 1,  3114,   47024,  102011,  113400,  113400, ...
  0, 1, 29004, 1331664, 5176504, 7235651, 7484400, ...

Crossrefs

Columns k=0-4 give: A000007, A000012, A220097, A266734, A266735.

Main diagonal gives A000680.

First lower diagonal gives A267532.

Cf. A214015, A267480.

Sequence in context: A340206 A196603 A318458 * A285824 A269955 A376731

Adjacent sequences: A267476 A267477 A267478 * A267480 A267481 A267482

Keyword

nonn,tabl

Author

Alois P. Heinz, Jan 15 2016

Status

approved