A322383 Number T(n,k) of entries in the k-th cycles of all permutations of [n] when cycles are ordered by increasing lengths (and increasing smallest elements); triangle T(n,k), n>=1, 1<=k<=n, read by rows.
1, 3, 1, 10, 7, 1, 45, 37, 13, 1, 236, 241, 101, 21, 1, 1505, 1661, 896, 226, 31, 1, 10914, 13301, 7967, 2612, 442, 43, 1, 90601, 117209, 78205, 29261, 6441, 785, 57, 1, 837304, 1150297, 827521, 346453, 88909, 14065, 1297, 73, 1, 8610129, 12314329, 9507454, 4338214, 1253104, 234646, 28006, 2026, 91, 1
Offset: 1
Examples
The 6 permutations of {1,2,3} are: (1) (2) (3) (1) (2,3) (2) (1,3) (3) (1,2) (1,2,3) (1,3,2) so there are 10 elements in the first cycles, 7 in the second cycles and only 1 in the third cycles. Triangle T(n,k) begins: 1; 3, 1; 10, 7, 1; 45, 37, 13, 1; 236, 241, 101, 21, 1; 1505, 1661, 896, 226, 31, 1; 10914, 13301, 7967, 2612, 442, 43, 1; 90601, 117209, 78205, 29261, 6441, 785, 57, 1; ...
Links
- Alois P. Heinz, Rows n = 1..141, flattened
- Andrew V. Sills, Integer Partitions Probability Distributions, arXiv:1912.05306 [math.CO], 2019.
- Wikipedia, Permutation
Crossrefs
Programs
-
Maple
b:= proc(n, l) option remember; `if`(n=0, add(l[i]* x^i, i=1..nops(l)), add(binomial(n-1, j-1)* b(n-j, sort([l[], j]))*(j-1)!, j=1..n)) end: T:= n-> (p-> (seq(coeff(p, x, i), i=1..n)))(b(n, [])): seq(T(n), n=1..12);
-
Mathematica
b[n_, l_] := b[n, l] = If[n == 0, l.x^Range[Length[l]], Sum[Binomial[n - 1, j - 1] b[n - j, Sort[Append[l, j]]] (j - 1)!, {j, 1, n}]]; T[n_] := Rest @ CoefficientList[b[n, {}], x]; Array[T, 12] // Flatten (* Jean-François Alcover, Mar 03 2020, after Alois P. Heinz *)