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.

A326649 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 distinct colors in increasing order.

Original entry on oeis.org

0, 1, 4, 19, 81, 413, 2439, 14655, 86844, 573196, 4224230, 32280154, 249433713, 1925416359, 15732592327, 139542345546, 1304524118159, 12445507282579, 119198874300879, 1137647406084952, 11183828252431175, 116368970786569604, 1278400213028604214
Offset: 0

Views

Author

Alois P. Heinz, Sep 12 2019

Keywords

Crossrefs

Programs

  • 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 or k b(n-t, min(n-t, i-1), k)*binomial(k, 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=h(n)..n):
    seq(a(n), n=0..25);
  • 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 || kJean-François Alcover, Dec 09 2020, after Alois P. Heinz *)

Formula

a(n) = Sum_{k=A185283(n)..n} k * A326616(n,k) = Sum_{k=A185283(n)..n} k * A326617(n,k).