A326616 Number T(n,k) of colored integer partitions of n using all colors of a k-set such that each block of part i with multiplicity j has a pattern of i*j distinct colors in increasing order; triangle T(n,k), n>=0, A185283(n)<=k<=n, read by rows.
1, 1, 2, 2, 5, 1, 9, 13, 9, 44, 42, 10, 96, 225, 150, 9, 152, 680, 1098, 576, 3, 155, 1350, 4155, 5201, 2266, 124, 2180, 11730, 26642, 26904, 9966, 140, 3751, 30300, 106281, 182000, 149832, 47466, 160, 6050, 69042, 348061, 896392, 1229760, 855240, 237019
Offset: 0
Examples
T(3,2) = 2: 2a1b, 2b1a. T(3,3) = 5: 3abc, 2ab1c, 2ac1b, 2bc1a, 111abc Triangle T(n,k) begins: 1; 1; 2; 2, 5; 1, 9, 13; 9, 44, 42; 10, 96, 225, 150; 9, 152, 680, 1098, 576; 3, 155, 1350, 4155, 5201, 2266; 124, 2180, 11730, 26642, 26904, 9966; 140, 3751, 30300, 106281, 182000, 149832, 47466; ...
Links
- Alois P. Heinz, Rows n = 0..200, flattened
- Wikipedia, Partition (number theory)
Crossrefs
Programs
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Maple
g:= proc(n) option remember; `if`(n=0, 0, numtheory[sigma](n)+g(n-1)) end: h:= proc(n) option remember; local k; for k from `if`(n=0, 0, h(n-1)) do if g(k)>=n then return k fi od end: b:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1, 0, add((t-> b(n-t, min(n-t, i-1), k)*binomial(k, t))(i*j), j=0..n/i))) end: T:= (n, k)-> add(b(n$2, k-i)*(-1)^i*binomial(k, i), i=0..k): seq(seq(T(n, k), k=h(n)..n), n=0..12);
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Mathematica
g[n_] := g[n] = If[n == 0, 0, DivisorSigma[1, n] + g[n - 1]]; h[n_] := h[n] = Module[{k}, For[k = If[n == 0, 0, h[n - 1]], True, k++, If[g[k] >= n, Return[k]]]]; b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i < 1, 0, Sum[Function[t, b[n - t, Min[n - t, i - 1], k]*Binomial[k, t]][i*j], {j, 0, n/i}]]]; T[n_, k_] := Sum[b[n, n, k - i]*(-1)^i*Binomial[k, i], {i, 0, k}]; Table[Table[T[n, k], {k, h[n], n}], {n, 0, 12}] // Flatten (* Jean-François Alcover, Feb 27 2021, after Alois P. Heinz *)
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