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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A185384 A binomial transform of Fibonacci numbers.

Original entry on oeis.org

1, 2, 1, 5, 6, 2, 13, 24, 15, 3, 34, 84, 78, 32, 5, 89, 275, 340, 210, 65, 8, 233, 864, 1335, 1100, 510, 126, 13, 610, 2639, 4893, 5040, 3115, 1155, 238, 21, 1597, 7896, 17080, 21112, 16310, 8064, 2492, 440, 34, 4181, 23256, 57492, 82908, 76860, 47502, 19572, 5184, 801, 55
Offset: 0

Views

Author

Emanuele Munarini, Feb 29 2012

Keywords

Comments

Triangle begins:
1,
2, 1,
5, 6, 2,
13, 24, 15, 3,
34, 84, 78, 32, 5,
89, 275, 340, 210, 65, 8,
233, 864, 1335, 1100, 510, 126, 13,
610, 2639, 4893, 5040, 3115, 1155, 238, 21,
1597, 7896, 17080, 21112, 16310, 8064, 2492, 440, 34,
...
Diagonal: a(n,n) = F(n+1).
First column: a(n,0) = F(2n+1) (A001519).
Row sums: Sum_{k=0..n} a(n,k) = F(3n+1) (A033887).
Alternated row sums: Sum_{k=0..n} (-1)^k * a(n,k) = 1.
Diagonal sums: Sum_{k=0..floor(n/2)} a(n-k,k) = A208481(n).
Alternated diagonal sums: Sum_{k=0..floor(n/2)} (-1)^k * a(n-k,k) = F(n+3)-1 (A000071).
Row square-sums: Sum_{k=0..n} a(n,k)^2 = A208588(n).
Central coefficients: a(2*n,n) = binomial(2n,n)*F(3n+1) (A208473), where F(n) are the Fibonacci numbers (A000045).
Mirror image of the triangle in A122070. - Philippe Deléham, Mar 13 2012
Subtriangle of (1, 1, 1, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (0, 1, 1, -1, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938. - Philippe Deléham, Mar 13 2012

Examples

			From _Philippe Deléham_, Mar 13 2012: (Start)
(1, 1, 1, 0, 0, 0, ...) DELTA (0, 1, 1, -1, 0, 0, ...) begins:
    1;
    1,   0;
    2,   1,    0;
    5,   6,    2,    0;
   13,  24,   15,    3,   0;
   34,  84,   78,   32,   5,   0;
   89, 275,  340,  210,  65,   8,  0;
  233, 864, 1335, 1100, 510, 126, 13, 0;
  ... (End)
		

Crossrefs

Programs

  • Mathematica
    Flatten[Table[Sum[Binomial[n,i]Binomial[i,k]Fibonacci[i+1],{i,k,n}],{n,0,20},{k,0,n}]]
    CoefficientList[Series[CoefficientList[Series[(1 - x)/(1 - 3*x + x^2 - x*y - x^2*y - x^2*y^2), {x, 0, 10}], x], {y, 0, 10}], y] // Flatten (* G. C. Greubel, Jun 28 2017 *)
  • Maxima
    create_list(binomial(n,k)*fib(2*n-k+1),n,0,20,k,0,n);
    
  • PARI
    for(n=0,10, for(k=0,n, print1(sum(i=k,n, binomial(n,i) * binomial(i,k) * fibonacci(i+1)), ", "))) \\ G. C. Greubel, Jun 28 2017

Formula

a(n,k) = Sum_{i=k..n} binomial(n,i)*binomial(i,k)*F(i+1).
a(n,k) = binomial(n,i) * Sum_{i=k..n} binomial(n-k,n-i)*F(i+1).
Explicit form: a(n,k) = binomial(n,k)*F(2*n-k+1).
G.f.: (1-x)/(1-3*x+x^2-x*y-x^2*y-x^2*y^2).
Recurrence: a(n+2,k+2) = 3*a(n+1,k+2) + a(n+1,k+1) - a(n,k+2) + a(n,k+1) + a(n,k).
T(n,k) = A122070(n,n-k). - Philippe Deléham, Mar 13 2012

A122070 Triangle given by T(n,k) = Fibonacci(n+k+1)*binomial(n,k) for 0<=k<=n.

Original entry on oeis.org

1, 1, 2, 2, 6, 5, 3, 15, 24, 13, 5, 32, 78, 84, 34, 8, 65, 210, 340, 275, 89, 13, 126, 510, 1100, 1335, 864, 233, 21, 238, 1155, 3115, 5040, 4893, 2639, 610, 34, 440, 2492, 8064, 16310, 21112, 17080, 7896, 1597, 55, 801, 5184, 19572, 47502, 76860, 82908, 57492, 23256, 4181
Offset: 0

Views

Author

Philippe Deléham, Oct 15 2006, Mar 13 2012

Keywords

Comments

Subtriangle of (0, 1, 1, -1, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (1, 1, 1, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938.
Mirror image of the triangle in A185384.

Examples

			Triangle begins:
   1;
   1,   2;
   2,   6,   5;
   3,  15,  24,   13;
   5,  32,  78,   84,   34;
   8,  65, 210,  340,  275,  89;
  13, 126, 510, 1100, 1335, 864, 233;
(0, 1, 1, -1, 0, 0, ...) DELTA (1, 1, 1, 0, 0, ...) begins :
  1;
  0,  1;
  0,  1,   2;
  0,  2,   6,   5;
  0,  3,  15,  24,   13;
  0,  5,  32,  78,   84,   34;
  0,  8,  65, 210,  340,  275,  89;
  0, 13, 126, 510, 1100, 1335, 864, 233;
		

Crossrefs

Programs

  • GAP
    Flat(List([0..10], n-> List([0..n], k-> Binomial(n,k)*Fibonacci(n+ k+1) ))); # G. C. Greubel, Oct 02 2019
  • Magma
    [Binomial(n,k)*Fibonacci(n+k+1): k in [0..n], n in [0..10]]; // G. C. Greubel, Oct 02 2019
    
  • Maple
    with(combinat): seq(seq(binomial(n,k)*fibonacci(n+k+1), k=0..n), n=0..10); # G. C. Greubel, Oct 02 2019
  • Mathematica
    Table[Fibonacci[n+k+1]*Binomial[n,k], {n,0,10}, {k,0,n}]//Flatten (* G. C. Greubel, Oct 02 2019 *)
  • PARI
    T(n,k) = binomial(n,k)*fibonacci(n+k+1);
    for(n=0,10, for(k=0,n, print1(T(n,k), ", "))) \\ G. C. Greubel, Oct 02 2019
    
  • Sage
    [[binomial(n,k)*fibonacci(n+k+1) for k in (0..n)] for n in (0..10)] # G. C. Greubel, Oct 02 2019
    

Formula

T(n,k) = A000045(n+k+1)*A007318(n,k) .
T(n,n) = Fibonacci(2*n+1) = A001519(n+1) .
Sum_{k=0..n} T(n,k) = Fibonacci(3*n+1) = A033887(n) .
Sum_{k=0..n}(-1)^k*T(n,k) = (-1)^n = A033999(n) .
Sum_{k=0..floor(n/2)} T(n-k,k) = (Fibonacci(n+1))^2 = A007598(n+1).
Sum_{k=0..n} T(n,k)*2^k = Fibonacci(4*n+1) = A033889(n).
Sum_{k=0..n} T(n,k)^2 = A208588(n).
G.f.: (1-y*x)/(1-(1+3y)*x-(1+y-y^2)*x^2).
T(n,k) = T(n-1,k) + 3*T(n-1,k-1) + T(n-2,k) + T(n-2,k-1) - T(n-2,k-2), T(0,0) = T(1,0) = 1, T(1,1) = 2, T(n,k) = 0 if k<0 or if k>n.
T(n,k) = A185384(n,n-k).
T(2n,n) = binomial(2n,n)*Fibonacci(3*n+1) = A208473(n).

Extensions

Corrected and extended by Philippe Deléham, Mar 13 2012
Term a(50) corrected by G. C. Greubel, Oct 02 2019
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