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.

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A290517 Maximum value of the multinomial coefficients M(n;lambda), where lambda ranges over all partitions of n into distinct parts.

Original entry on oeis.org

1, 1, 1, 3, 4, 10, 60, 105, 280, 1260, 12600, 27720, 83160, 360360, 2522520, 37837800, 100900800, 343062720, 1543782240, 9777287520, 97772875200, 2053230379200, 6453009763200, 24736537425600, 118735379642880, 742096122768000, 6431499730656000
Offset: 0

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Author

Alois P. Heinz, Aug 04 2017

Keywords

Examples

			a(10) = 12600 = 10! / (4! * 3! * 2! * 1!) is the value for partition [4,3,2,1]. All other partitions of 10 into distinct parts give smaller values: [5,3,2]-> 2520, [5,4,1]-> 1260, [6,3,1]-> 840, [6,4]-> 210, [7,2,1]-> 360, [7,3]-> 120, [8,2]-> 45, [9,1]-> 10, [10]-> 1.
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n>i*(i+1)/2, infinity,
         `if`(n=0, 1, min(b(n, i-1), b(n-i, min(n-i, i-1))*i!)))
        end:
    a:= n-> n!/b(n$2):
    seq(a(n), n=0..30);
    # second Maple program:
    a:= proc(n) option remember; `if`(n=0, 1, a(n-1)*n/
          (t-> t*(t+3)/2-n+2)(floor(sqrt(8*n-7)/2-1/2)))
        end:
    seq(a(n), n=0..30);  # Alois P. Heinz, Aug 05 2017
  • Mathematica
    b[n_, i_]:=b[n, i]=If[n>i*(i + 1)/2, Infinity, If[n==0, 1, Min[b[n, i - 1], b[n - i, Min[n - i, i - 1]]*i!]]]; Table[n!/b[n, n], {n, 0, 30}] (* Indranil Ghosh, Aug 05 2017, after Maple *)

Formula

a(n) = A000142(n) / A290518(n).
a(0) = 1, a(n) = n * a(n-1) / A004736(n) for n>0.
a(n) = A309992(n,A000009(n)). - Alois P. Heinz, Aug 26 2019
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