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.

A093784 Triangle T(n,k) read by rows in which n-th row gives the hook products of the partitions of n.

Original entry on oeis.org

1, 1, 2, 2, 3, 6, 6, 8, 8, 12, 24, 24, 20, 24, 24, 30, 30, 120, 120, 45, 72, 72, 80, 80, 144, 144, 144, 144, 720, 720, 144, 144, 240, 240, 252, 336, 336, 360, 360, 360, 360, 840, 840, 5040, 5040, 448, 576, 576, 630, 630, 720, 720, 960, 1152, 1152, 1440, 1440, 1920
Offset: 0

Views

Author

Emeric Deutsch, May 17 2004

Keywords

Comments

Row n consists of the numbers n!/A060240(n,k) written in reverse order.

Examples

			Triangle T(n,k) begins:
   1;
   1;
   2,  2;
   3,  6,  6;
   8,  8, 12, 24, 24;
  20, 24, 24, 30, 30, 120, 120;
  45, 72, 72, 80, 80, 144, 144, 144, 144, 720, 720;
  ...
		

Crossrefs

Programs

  • Maple
    H:=proc(pa) local F,j,p,Q,i,col,a,A: F:=proc(x) local i, ct: ct:=0: for i from 1 to nops(x) do if x[i]>1 then ct:=ct+1 else fi od: ct; end: for j from 1 to nops(pa) do p[1][j]:=pa[j] od: Q[1]:=[seq(p[1][j],j=1..nops(pa))]: for i from 2 to pa[1] do for j from 1 to F(Q[i-1]) do p[i][j]:=Q[i-1][j]-1 od: Q[i]:=[seq(p[i][j],j=1..F(Q[i-1]))] od: for i from 1 to pa[1] do col[i]:=[seq(Q[i][j]+nops(Q[i])-j,j=1..nops(Q[i]))] od: a:=proc(i,j) if i<=nops(Q[j]) and j<=pa[1] then Q[j][i]+nops(Q[j])-i else 1 fi end: A:=matrix(nops(pa),pa[1],a): product(product(A[m,n],n=1..pa[1]),m=1..nops(pa)); end: with(combinat): rev:=proc(a) [seq(a[nops(a)+1-i],i=1..nops(a))] end: seq(sort([seq(H(rev(partition(s)[q])),q=1..numbpart(s))]),s=1..9);
    # second Maple program:
    h:= proc(l) local n; n:= nops(l); mul(mul(1+l[i]-j+
          add(`if`(l[k]>=j, 1, 0), k=i+1..n), j=1..l[i]), i=1..n) end:
    g:= (n, i, l)-> `if`(n=0 or i=1, h([l[], 1$n]), `if`(i<1, 0,
                     seq(g(n-i*j, i-1, [l[], i$j]), j=0..n/i))):
    T:= n-> sort([g(n, n, [])])[]:
    seq(T(n), n=0..10);  # Alois P. Heinz, Jan 07 2013
  • Mathematica
    h[l_List] := With[{n = Length[l]},  Product[Product[1+l[[i]]-j+Sum[If[l[[k]] >= j, 1, 0], {k, i+1, n}], {j, 1, l[[i]]}], {i, 1, n}]]; g[1, 1, {}] = {1}; g[n_, i_, l_List] := If[n == 0 || i == 1, h[Join[l, Array[1&, n]]], If[i<1, 0, Flatten @  Table[g[n-i*j, i-1, Join[l, Array[i&, j]]], {j, 0, n/i}]]]; T[n_] := Sort[g[n, n, {}]]; Table[T[n], {n, 1, 10}] // Flatten (* Jean-François Alcover, Apr 29 2015, after Alois P. Heinz *)