cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A326656 Total number of colors in all colored integer partitions of n using all colors of an initial interval of the color palette such that each block of part i with multiplicity j has a pattern of i*j colors in (weakly) increasing order.

Original entry on oeis.org

0, 1, 6, 34, 191, 1208, 7840, 54152, 377396, 2868528, 22719712, 187318016, 1594593876, 13795808224, 125535871760, 1192418406800, 11747646588912, 118703814213296, 1223646182128656, 12755728151091424, 137199027931128992, 1527404635450188128, 17599899510211606336
Offset: 0

Views

Author

Alois P. Heinz, Sep 12 2019

Keywords

Crossrefs

Cf. A326500.

Programs

  • Maple
    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-1, t))(i*j), j=0..n/i)))
        end:
    a:= n-> add(k*add(b(n$2, k-i)*(-1)^i*binomial(k, i), i=0..k), k=0..n):
    seq(a(n), n=0..25);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n==0, 1, If[i < 1, 0, Sum[With[{t = i j}, b[n - t, Min[n - t, i - 1], k]*Binomial[k + t - 1, t]], {j, 0, n/i}]]];
    a[n_] := Sum[k Sum[b[n, n, k-i] (-1)^i Binomial[k, i], {i, 0, k}], {k, 0, n}];
    a /@ Range[0, 25] (* Jean-François Alcover, Dec 15 2020, after Alois P. Heinz *)

Formula

a(n) = Sum_{k=1..n} k * A326500(n,k).