A342861 Irregular table read by rows: T(n,k) is the number of permutations in S_n that have exactly k occurrences of the pattern 1324. 0 <= k <= A342853(n).

1, 1, 2, 6, 23, 1, 103, 10, 6, 1, 513, 75, 74, 26, 17, 9, 6, 2762, 522, 645, 321, 290, 130, 166, 47, 54, 48, 41, 4, 8, 2, 15793, 3579, 5023, 3058, 3232, 1527, 2228, 874, 1159, 893, 875, 340, 503, 281, 269, 207, 156, 112, 123, 21, 54, 2, 0, 6, 5

Offset

0,3

Comments

Equivalently the table for the pattern 4231.

First column is A061552.

Links

Peter Kagey, Rows n = 0..13, flattened, based on Anders Kaseorg's Rust program in the Code Golf Stack Exchange link.

FindStat St000405: The number of occurrences of the pattern 1324 in a permutation.

Anders Kaseorg, Answer: Patterns in Permutations, Code Golf Stack Exchange.

Example

Triangle begins:
  n\k|       0        1        2        3        4        5        6
  ---+-------------------------------------------------------------------
   0 |       1;
   1 |       1;
   2 |       2;
   3 |       6;
   4 |      23,       1;
   5 |     103,      10,       6,       1;
   6 |     513,      75,      74,      26,      17,       9,       6;
   7 |    2762,     522,     645,     321,     290,     130,     166, ...
   8 |   15793,    3579,    5023,    3058,    3232,    1527,    2228, ...
   9 |   94776,   24670,   37549,   26174,   30409,   15966,   23762, ...
  10 |  591950,  172198,  277089,  213122,  264667,  154452,  228665, ...
  11 | 3824112, 1219974, 2043416, 1693787, 2213548, 1420513, 2086877, ...

Crossrefs

Cf. A061552, A342853.

Analogous for other patterns: A008302 (12), A138159 (321), A263771 (312), A342840 (1342), A342860 (2413), A342862 (2143), A342863 (1243), A342864 (1432), A342865 (1234).

Sequence in context: A140837 A342860 A342840 * A342862 A342863 A342864

Adjacent sequences: A342858 A342859 A342860 * A342862 A342863 A342864

Keyword

nonn,tabf

Author

Peter Kagey, Mar 26 2021

Status

approved