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.

A327680 Total number of colors used in all colored integer partitions of n using all colors of an initial interval of the color palette such that parts i have distinct color patterns in arbitrary order and each pattern for a part i has i colors in (weakly) increasing order.

Original entry on oeis.org

0, 1, 7, 44, 358, 2904, 29112, 296448, 3520568, 43482208, 602603120, 8712724080, 138736978208, 2302036052128, 41417364992160, 776413790063328, 15597709327298944, 325945020056535968, 7238587734613470208, 166897326948551436384, 4061690336695535982048
Offset: 0

Views

Author

Alois P. Heinz, Sep 21 2019

Keywords

Crossrefs

Cf. A309973.

Programs

  • Maple
    b:= proc(n, i, k) option remember; `if`(n=0, 1,
          `if`(i<1, 0, add(b(n-i*j, min(n-i*j, i-1), k)*
           binomial(binomial(k+i-1, i), j)*j!, j=0..n/i)))
        end:
    a:= n-> add(add(k*b(n$2, i)*(-1)^(k-i)*
            binomial(k, i), i=0..k), k=0..n):
    seq(a(n), n=0..22);
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i < 1, 0, Sum[b[n - i*j, Min[n - i*j, i-1], k] Binomial[Binomial[k+i-1, i], j] j!, {j, 0, n/i}]]];
    a[n_] := Sum[Sum[k b[n, n, i](-1)^(k-i)Binomial[k, i], {i, 0, k}], {k, 0, n}];
    a /@ Range[0, 22] (* Jean-François Alcover, Dec 18 2020, after_Alois P. Heinz_ *)

Formula

a(n) = Sum_{k=1..n} k * A309973(n,k).