A322384 Number T(n,k) of entries in the k-th cycles of all permutations of [n] when cycles are ordered by decreasing lengths (and increasing smallest elements); triangle T(n,k), n>=1, 1<=k<=n, read by rows.
1, 3, 1, 13, 4, 1, 67, 21, 7, 1, 411, 131, 46, 11, 1, 2911, 950, 341, 101, 16, 1, 23563, 7694, 2871, 932, 197, 22, 1, 213543, 70343, 26797, 9185, 2311, 351, 29, 1, 2149927, 709015, 275353, 98317, 27568, 5119, 583, 37, 1, 23759791, 7867174, 3090544, 1141614, 343909, 73639, 10366, 916, 46, 1
Offset: 1
Examples
The 6 permutations of {1,2,3} are: (1) (2) (3) (1,2) (3) (1,3) (2) (2,3) (1) (1,2,3) (1,3,2) so there are 13 elements in the first cycles, 4 in the second cycles and only 1 in the third cycles. Triangle T(n,k) begins: 1; 3, 1; 13, 4, 1; 67, 21, 7, 1; 411, 131, 46, 11, 1; 2911, 950, 341, 101, 16, 1; 23563, 7694, 2871, 932, 197, 22, 1; 213543, 70343, 26797, 9185, 2311, 351, 29, 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
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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);
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Mathematica
b[n_, l_] := b[n, l] = If[n == 0, Sum[l[[-i]]*x^i, {i, 1, Length[l]}], Sum[Binomial[n-1, j-1]*b[n-j, Sort[Append[l, j]]]*(j-1)!, {j, 1, n}]]; T[n_] := CoefficientList[b[n, {}], x] // Rest; Array[T, 12] // Flatten (* Jean-François Alcover, Feb 26 2020, after Alois P. Heinz *)