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.

A106198 Triangle, columns = successive binomial transforms of Fibonacci numbers.

Original entry on oeis.org

1, 1, 1, 2, 2, 1, 3, 5, 3, 1, 5, 13, 10, 4, 1, 8, 34, 35, 17, 5, 1, 13, 89, 125, 75, 26, 6, 1, 21, 233, 450, 338, 139, 37, 7, 1, 34, 610, 1625, 1541, 757, 233, 50, 8, 1
Offset: 0

Views

Author

Gary W. Adamson, Apr 24 2005

Keywords

Comments

Column 0 = Fibonacci numbers, column 1 = odd-indexed Fibonacci numbers (first binomial transform of 1, 1, 2, 3, 5, ...); column 2 = second binomial transform of Fibonacci numbers, etc.

Examples

			First few rows of the triangle are:
   1;
   1,   1;
   2,   2,   1;
   3,   5,   3,   1;
   5,  13,  10,   4,   1;
   8,  34,  35,  17,   5,   1;
  13,  89, 125,  75,  26,   6,   1;
  21, 233, 450, 338, 139,  37,   7,   1;
  ...
Column 2 = A081567, second binomial transform of Fibonacci numbers: 1, 3, 10, 35, 125, ...
		

Crossrefs

Programs

  • GAP
    T:= function(n,k)
        if k=0 then return Fibonacci(n+1);
        else return Sum([0..n-k], j-> Binomial(n-k,j)*Fibonacci(j+1)*k^(n-k-j));
        fi; end;
    Flat(List([0..10], n-> List([0..n], k-> T(n,k) ))); # G. C. Greubel, Dec 11 2019
  • Magma
    function T(n,k)
      if k eq 0 then return Fibonacci(n+1);
      else return (&+[Binomial(n-k,j)*Fibonacci(j+1)*k^(n-k-j): j in [0..n-k]]);
      end if; return T; end function;
    [T(n,k): k in [0..n], n in [0..10]]; // G. C. Greubel, Dec 11 2019
    
  • Maple
    with(combinat);
    T:= proc(n, k) option remember;
          if k=0 then fibonacci(n+1)
        else add( binomial(n-k,j)*fibonacci(j+1)*k^(n-k-j), j=0..n-k)
          fi; end:
    seq(seq(T(n, k), k=0..n), n=0..10); # G. C. Greubel, Dec 11 2019
  • Mathematica
    Table[If[k==0, Fibonacci[n+1], Sum[Binomial[n-k, j]*Fibonacci[j+1]*k^(n-k-j), {j,0,n-k}]], {n,0,10}, {k,0,n}]//Flatten (* G. C. Greubel, Dec 11 2019 *)
  • PARI
    T(n,k) = if(k==0, fibonacci(n+1), sum(j=0,n-k, binomial(n-k,j)*fibonacci( j+1)*k^(n-k-j)) ); \\ G. C. Greubel, Dec 11 2019
    
  • Sage
    @CachedFunction
    def T(n, k):
        if (k==0): return fibonacci(n+1)
        else: return sum(binomial(n-k,j)*fibonacci(j+1)*k^(n-k-j) for j in (0..n-k))
    [[T(n, k) for k in (0..n)] for n in (0..10)] # G. C. Greubel, Dec 11 2019
    

Formula

Offset column k = k-th binomial transform of the Fibonacci numbers, given leftmost column = Fibonacci numbers.