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.

A157898 Triangle read by rows: inverse binomial transform of A059576.

Original entry on oeis.org

1, 0, 1, 1, 1, 2, 0, 2, 2, 4, 1, 2, 6, 4, 8, 0, 3, 6, 16, 8, 16, 1, 3, 12, 16, 40, 16, 32, 0, 4, 12, 40, 40, 96, 32, 64, 1, 4, 20, 40, 120, 96, 224, 64, 128, 0, 5, 20, 80, 120, 336, 224, 512, 128, 256
Offset: 0

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Author

Gary W. Adamson and Roger L. Bagula, Mar 08 2009

Keywords

Comments

The inverse binomial transform of the triangle A059576 is given by multiplying the triangle with A130595 from the left.

Examples

			First few rows of the triangle =
  1;
  0, 1;
  1, 1,  2;
  0, 2,  2,  4;
  1, 2,  6,  4,   8;
  0, 3,  6, 16,   8,  16;
  1, 3, 12, 16,  40,  16,  32;
  0, 4, 12, 40,  40,  96,  32,  64;
  1, 4, 20, 40, 120,  96, 224,  64, 128;
  0, 5, 20, 80, 120, 336, 224, 512, 128, 256;
  ...
		

Crossrefs

Programs

  • Magma
    A011782:= func< n | n eq 0 select 1 else 2^(n-1) >;
    function t(n, k) // t = A059576
      if k eq 0 or k eq n then return A011782(n);
      else return 2*t(n-1, k-1) + 2*t(n-1, k) - (2 - 0^(n-2))*t(n-2, k-1);
      end if; return t;
    end function;
    A157898:= func< n,k | (&+[(-1)^(n-j)*Binomial(n,j)*t(j,k): j in [k..n]]) >;
    [A157898(n, k): k in [0..n], n in [0..12]]; // G. C. Greubel, Sep 03 2022
    
  • Maple
    A059576 := proc (n, k)
        if n = 0 then
            return 1;
        end if;
        if k <= n and k >= 0 then
            add((-1)^j*2^(n-j-1)*binomial(k, j)*binomial(n-j, k), j = 0 .. min(k, n-k))
        else
            0 ;
        end if
    end proc:
    A157898 := proc(n,k)
        add ( A130595(n,j)*A059576(j,k),j=k..n) ;
    end proc: # R. J. Mathar, Feb 13 2013
  • Mathematica
    t[n_, k_]:= t[n, k]= If[k==0 || k==n, 2^(n-1) +Boole[n==0]/2, 2*t[n-1, k-1] + 2*t[n-1, k] -(2 -Boole[n==2])*t[n-2, k-1]]; (* t= A059576 *)
    A157898[n_, k_]:= A157898[n, k]= Sum[(-1)^(n-j)*Binomial[n,j]*t[j,k], {j,k,n}];
    Table[A157898[n, k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Sep 03 2022 *)
  • SageMath
    @CachedFunction
    def t(n, k): # t = A059576
        if (k==0 or k==n): return bool(n==0)/2 + 2^(n-1) # A011782
        else: return 2*t(n-1, k-1) + 2*t(n-1, k) - (2 - 0^(n-2))*t(n-2, k-1)
    def A157898(n,k): return sum((-1)^(n-j)*binomial(n,j)*t(j,k) for j in (k..n))
    flatten([[A157898(n, k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Sep 03 2022

Formula

Sum_{k=0..n} T(n, k) = A097076(n+1).
From G. C. Greubel, Sep 03 2022: (Start)
T(n, k) = Sum_{j=k..n} (-1)^(n-j)*binomial(n,j)*A059576(j,k).
T(n, 0) = A059841(n).
T(n, 1) = A004526(n-1).
T(n, 2) = 2*A008805(n-2).
T(n, 3) = 4*A058187(n-3).
T(n, 4) = 8*A189976(n+4).
T(n, n) = A011782(n).
T(n, n-1) = A011782(n) - [n==0]. (End)