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.

Showing 1-3 of 3 results.

A059365 Another version of the Catalan triangle: T(r,s) = binomial(2*r-s-1,r-1) - binomial(2*r-s-1,r), r>=0, 0 <= s <= r.

Original entry on oeis.org

0, 0, 1, 0, 1, 1, 0, 2, 2, 1, 0, 5, 5, 3, 1, 0, 14, 14, 9, 4, 1, 0, 42, 42, 28, 14, 5, 1, 0, 132, 132, 90, 48, 20, 6, 1, 0, 429, 429, 297, 165, 75, 27, 7, 1, 0, 1430, 1430, 1001, 572, 275, 110, 35, 8, 1, 0, 4862, 4862, 3432, 2002, 1001, 429, 154, 44
Offset: 0

Views

Author

N. J. A. Sloane, Jan 28 2001

Keywords

Examples

			Triangle starts
  0;
  0,    1;
  0,    1,    1;
  0,    2,    2,    1;
  0,    5,    5,    3,    1;
  0,   14,   14,    9,    4,    1;
  0,   42,   42,   28,   14,    5,   1;
  0,  132,  132,   90,   48,   20,   6,   1;
  0,  429,  429,  297,  165,   75,  27,   7,  1;
  0, 1430, 1430, 1001,  572,  275, 110,  35,  8, 1;
  0, 4862, 4862, 3432, 2002, 1001, 429, 154, 44, 9, 1;
  ...
		

Crossrefs

See also the triangle in A009766. First 2 diagonals both give A000108, next give A000245, A002057.
The three triangles A059365, A106566 and A099039 are the same except for signs and the leading term.
Essentially the same as A033184.
The following are all versions of (essentially) the same Catalan triangle: A009766, A030237, A033184, A053121, A059365, A099039, A106566, A130020, A047072, A171567, A181645.

Programs

  • Magma
    /* as triangle */ [[[0] cat [Binomial(2*r-s-1, r-1)- Binomial(2*r-s-1, r): s in [1..r]]: r in [0..10]]]; // Vincenzo Librandi, Jan 09 2017
  • Mathematica
    Table[Binomial[2*r - s - 1, r - 1] - Binomial[2*r - s - 1, r], {r, 0, 10}, {s, 0, r}] // Flatten (* G. C. Greubel, Jan 08 2017 *)
  • PARI
    tabl(nn) = { print(0); for (r=1, nn, for (s=0, r, print1(binomial(2*r-s-1,r-1)-binomial(2*r-s-1,r), ", ");); print(););}  \\ Michel Marcus, Nov 01 2013
    

Formula

Essentially the same triangle as [0, 1, 1, 1, 1, 1, 1, ...] DELTA A000007, where DELTA is Deléham's operator defined in A084938, but the first term is T(0,0) = 0.

A154930 Inverse of Fibonacci convolution array A154929.

Original entry on oeis.org

1, -2, 1, 5, -4, 1, -15, 14, -6, 1, 51, -50, 27, -8, 1, -188, 187, -113, 44, -10, 1, 731, -730, 468, -212, 65, -12, 1, -2950, 2949, -1956, 970, -355, 90, -14, 1, 12235, -12234, 8291, -4356, 1785, -550, 119, -16, 1, -51822, 51821, -35643, 19474, -8612, 3021
Offset: 0

Views

Author

Paul Barry, Jan 17 2009

Keywords

Comments

Alternating sign version of A104259. Row sums are (-1)^n*A033321. First column is (-1)^n*A007317.

Examples

			Triangle begins
1,
-2, 1,
5, -4, 1,
-15, 14, -6, 1,
51, -50, 27, -8, 1,
-188, 187, -113, 44, -10, 1,
731, -730, 468, -212, 65, -12, 1,
-2950, 2949, -1956, 970, -355, 90, -14, 1
Production array is
-2, 1,
1, -2, 1,
-1, 1, -2, 1,
1, -1, 1, -2, 1,
-1, 1, -1, 1, -2, 1,
1, -1, 1, -1, 1, -2, 1,
-1, 1, -1, 1, -1, 1, -2, 1
or ((1-x-x^2)/(1+x),x) beheaded.
		

Crossrefs

Formula

Riordan array ((1/(1+x))c(-x/(1+x)), (x/(1+x))c(x/(1+x))), c(x) the g.f. of A000108;
Riordan array ((sqrt(1+6x+5x^2)-x-1)/(2x(1+x)),(sqrt(1+6x+5x^2)-x-1)/ (2(1+x)));
Triangle T(n,k) = sum{j=0..n, (-1)^(n-k)*C(n,j)*C(2j-k,j-k)(k+1)/(j+1)}.
T(n,k) = T(n-1,k-1) -2*T(n-1,k) + Sum_{i, i>=0} T(n-1,k+1+i)*(-1)^i. - Philippe Deléham, Feb 23 2012

A189675 Composition of Catalan and Fibonacci numbers.

Original entry on oeis.org

1, -1, 2, 2, -4, 3, -5, 10, -9, 5, 14, -28, 27, -20, 8, -42, 84, -84, 70, -40, 13, 132, -264, 270, -240, 160, -78, 21, -429, 858, -891, 825, -600, 351, -147, 34, 1430, -2860, 3003, -2860, 2200, -1430, 735, -272, 55, -4862, 9724, -10296, 10010, -8008, 5577, -3234, 1496, -495, 89, 16796, -33592, 35802, -35360, 29120, -21294, 13377, -7072, 2970, -890, 144, -58786, 117572, -125970, 125970, -106080, 80444, -53508, 30940, -15015, 5785, -1584, 233
Offset: 1

Views

Author

Wouter Meeussen, Apr 25 2011

Keywords

Comments

Row sums equal 1 (proof by Bill Gosper, Apr 17 2011). Row sums of absolute terms equal A081696.

Examples

			Table starts
   1,
  -1,  2,
   2, -4,  3,
  -5, 10, -9, 5,
		

References

  • Email of R. W. Gosper on the math-fun mailing list, Apr 17 2011.

Crossrefs

Programs

  • Mathematica
    Table[(-1)^(k + n) k/(2n - k) Binomial[2n - k, n - k] Fibonacci[k + 1], {n, 12}, {k, n}]
Showing 1-3 of 3 results.