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.

A117195 Triangle read by rows: T(n,k) = number of partitions into distinct parts having rank k, 0<=k

Original entry on oeis.org

1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 2, 1, 1, 1, 0, 1, 1, 0, 2, 1, 2, 1, 1, 1, 0, 1, 0, 1, 1, 2, 2, 2, 1, 1, 1, 0, 1, 0, 1, 2, 2, 2, 2, 2, 1, 1, 1, 0, 1, 0, 1, 1, 3, 2, 3, 2, 2, 1, 1, 1, 0, 1, 0, 1, 2, 2, 4, 2, 3, 2, 2, 1, 1, 1, 0, 1
Offset: 1

Views

Author

Reinhard Zumkeller, Mar 03 2006

Keywords

Comments

T(n,0) = A010054(n), T(n,1) = 1-A010054(n) for n>1;
A000009(n) = Sum(T(n,k): 0<=k
A117192(n) = Sum(T(n,k)*(1 - k mod 2): 0<=k
A117193(n) = Sum(T(n,k)*(k mod 2): 0<=k
A117194(n) = Sum(T(n,k)*(1 - k mod 2): 0

Examples

			Triangle starts:
[ 1]   1,
[ 2]   0, 1,
[ 3]   1, 0, 1,
[ 4]   0, 1, 0, 1,
[ 5]   0, 1, 1, 0, 1,
[ 6]   1, 0, 1, 1, 0, 1,
[ 7]   0, 1, 1, 1, 1, 0, 1,
[ 8]   0, 1, 1, 1, 1, 1, 0, 1,
[ 9]   0, 1, 1, 2, 1, 1, 1, 0, 1,
[10]   1, 0, 2, 1, 2, 1, 1, 1, 0, 1,
[11]   0, 1, 1, 2, 2, 2, 1, 1, 1, 0, 1,
[12]   0, 1, 2, 2, 2, 2, 2, 1, 1, 1, 0, 1,
[13]   0, 1, 1, 3, 2, 3, 2, 2, 1, 1, 1, 0, 1,
[14]   0, 1, 2, 2, 4, 2, 3, 2, 2, 1, 1, 1, 0, 1, ...
T(12,0) = #{} = 0,
T(12,1) = #{5+4+2+1} = 1,
T(12,2) = #{6+3+2+1, 5+4+3} = 2,
T(12,3) = #{6+5+1, 6+4+2} = 2,
T(12,4) = #{7+4+1, 7+3+2} = 2,
T(12,5) = #{8+3+1, 7+5} = 2,
T(12,6) = #{9+2+1, 8+4} = 2,
T(12,7) = #{9+3} = 1,
T(12,8) = #{10+2} = 1,
T(12,9) = #{11+1} = 1,
T(12,10) = #{} = 0,
T(12,11) = #{12} = 1.
		

Crossrefs

Programs

  • Maple
    b:= proc(n, i, k) option remember;
          if n<0 or k<0 then []
        elif n=0 then [0$k, 1]
        elif i<1 then []
        else zip ((x, y)-> x+y, b(n, i-1, k), b(n-i, i-1, k-1), 0)
          fi
        end:
    T:= proc(n) local j, r; r:= [];
          for j from 0 to n do
            r:= zip ((x, y)-> x+y, r, b(n-j, j-1, j-1), 0)
          od; r[]
        end:
    seq (T(n), n=1..20);  # Alois P. Heinz, Aug 29 2011
  • Mathematica
    b[n_, i_, k_] := b[n, i, k] = Which[n<0 || k<0, {}, n == 0, Append[Array[0&, k], 1], i<1, {}, True, Plus @@ PadRight[{b[n, i-1, k], b[n-i, i-1, k-1]}]]; T[n_] := Module[{j, r}, r = {}; For[j = 0, j <= n, j++, r = Plus @@ PadRight[{r, b[n-j, j-1, j-1]}]]; r]; Table[T[n], {n, 1, 20}] // Flatten (* Jean-François Alcover, Jan 30 2014, after Alois P. Heinz *)
  • PARI
    N=33;  L=1+2*ceil(sqrtint(N));
    q='q+O(q^N);
    gf=sum(n=1,L, q^(n*(n+1)/2) / prod(k=1,n,1-z*q^k) );
    v=Vec(gf);
    { for (n=1,#v,  /* print triangle: */
        p = Pol(v[n], 'z) + 'c0;
        p = polrecip(p);
        rw = Vec(p);  rw[1] -= 'c0;
        print1("[", n, "]   " );
        print( rw );
    ); }
    /* Joerg Arndt, Oct 07 2012 */

Formula

G.f.: sum(n>=1, q^(n*(n+1)/2) / prod(k=1..n, 1-z*q^k) ), see Monks reference. [Joerg Arndt, Oct 07 2012]