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.

A327115 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 all parts have different color patterns and a pattern for part i has i distinct colors in increasing order.

Original entry on oeis.org

0, 1, 4, 19, 98, 570, 3642, 25292, 189454, 1519648, 12978141, 117437020, 1121299471, 11256640012, 118443403699, 1302670531063, 14938986954323, 178248001223476, 2208487163394749, 28363722744050886, 376991516806826090, 5178009641895235269, 73396161423153313320
Offset: 0

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Author

Alois P. Heinz, Sep 13 2019

Keywords

Examples

			a(2) = 4: 2ab, 1a1b.  Both colors (a and b) are used twice: 2 + 2 = 4.
		

Crossrefs

Programs

  • Maple
    C:= binomial:
    g:= proc(n) option remember; n*2^(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 or k add(k*add(b(n$2, i)*(-1)^(k-i)*C(k, i), i=0..k), k=h(n)..n):
    seq(a(n), n=0..23);
  • Mathematica
    c = Binomial;
    g[n_] := g[n] = n 2^(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 || k < h[n], 0, Sum[b[n - i j, Min[n - i j, i - 1], k] c[c[k, i], j], {j, 0, n/i}]]];
    a[n_] := Sum[k Sum[b[n, n, i] (-1)^(k-i) c[k, i], {i, 0, k}], {k, h[n], n}];
    a /@ Range[0, 23] (* Jean-François Alcover, Dec 09 2020, after Alois P. Heinz *)

Formula

a(n) = Sum_{k=1..n} A326914(n,k) = Sum_{k=1..n} A326962(n,k).