A342860 Irregular table read by rows: T(n,k) is the number of permutations in S_n that have exactly k occurrences of the pattern 2413. 0 <= k <= A342854(n).
1, 1, 2, 6, 23, 1, 103, 9, 8, 512, 62, 82, 34, 28, 2, 2740, 402, 612, 384, 466, 94, 232, 42, 60, 8, 15485, 2593, 4187, 3036, 4356, 1746, 3132, 1064, 1918, 909, 654, 333, 612, 144, 104, 22, 24, 1, 91245, 16921, 28065, 21638, 33274, 17598, 31180, 12942, 24000, 14290, 15434, 7770, 15692, 5965, 6896, 3947, 5660, 2226, 3674, 1314, 1512, 516, 508, 204, 332, 37, 40
Offset: 0
Examples
Triangle begins: n\k| 0 1 2 3 4 5 6 ---+------------------------------------------------------------------ 0 | 1; 1 | 1; 2 | 2; 3 | 6; 4 | 23, 1; 5 | 103, 9, 8; 6 | 512, 62, 82, 34, 28, 2; 7 | 2740, 402, 612, 384, 466, 94, 232, ... 8 | 15485, 2593, 4187, 3036, 4356, 1746, 3132, ... 9 | 91245, 16921, 28065, 21638, 33274, 17598, 31180, ... 10 | 555662, 112196, 188514, 149946, 237128, 140954, 257686, ... 11 | 3475090, 755920, 1278590, 1036826, 1658064, 1041598, 1933438, ...
Links
- Peter Kagey, Rows n = 0..13, flattened, based on Anders Kaseorg's Rust program in the Code Golf Stack Exchange link.
- Anders Kaseorg, Answer: Patterns in Permutations, Code Golf Stack Exchange.
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