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.

A097761 Inverse of binomial transform of Whitney triangle.

Original entry on oeis.org

1, -2, 1, 4, -4, 1, -10, 13, -6, 1, 28, -42, 26, -8, 1, -84, 138, -102, 43, -10, 1, 264, -462, 385, -198, 64, -12, 1, -858, 1573, -1430, 845, -338, 89, -14, 1, 2860, -5434, 5278, -3458, 1610, -530, 118, -16, 1, -9724, 19006, -19448, 13804, -7208, 2788, -782, 151, -18, 1, 33592
Offset: 0

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Author

Paul Barry, Aug 23 2004

Keywords

Comments

As an element of the Riordan group, this is ((1-x*C(-x))*C(-x), x*C(-x)^2), where C(x) = (1-(1-4*x)^(1/2))/(2*x) is the g.f. for Catalan numbers, A000108.
Inverse of A097750.
Row sums have g.f. (1-x*C(-x))*C(-x)/(1-x*C(-x)^2), or 1,-1,1,-2,5,-14,42,...

Examples

			Rows begin:
  {1},
  {-2,1},
  {4,-4,1},
  {-10,13,-6,1},
  ...
		

A131250 A007318 * A004070.

Original entry on oeis.org

1, 2, 1, 4, 4, 1, 8, 11, 6, 1, 16, 26, 22, 8, 1, 32, 57, 64, 37, 10, 1, 64, 120, 163, 130, 56, 12, 1, 128, 247, 382, 386, 232, 79, 14, 1, 256, 502, 848, 1024, 794, 378, 106, 16, 1, 512, 1013, 1816, 2510, 2380, 1471, 576, 137, 18, 1
Offset: 0

Views

Author

Gary W. Adamson, Jun 23 2007

Keywords

Comments

Row sums = A061667: (1, 3, 9, 26, 73, 201, ...).
Companion triangle = A131249 = A007318 * A052509, where A052509 is the reversal of A004070.
Reversal of A097750. - Philippe Deléham, Jan 11 2014
Riordan array (1/(1-2x), x/(1-x)^2). - Philippe Deléham, Jan 11 2014
Diagonal sums are A045623. - Philippe Deléham, Jan 11 2014

Examples

			First few rows of the triangle:
   1;
   2,  1;
   4,  4,  1;
   8, 11,  6,  1;
  16, 26, 22,  8,  1;
  32, 57, 64, 37, 10,  1;
  ...
		

Crossrefs

Formula

Binomial transform of A004070.
T(n,k) = 2*T(n-1,k) + T(n-1,k-1) - T(n-2,k), T(0,0)=1, T(n,k)=0 if k < 0 or if k > n. - Philippe Deléham, Jan 11 2014

Extensions

More terms from Philippe Deléham, Jan 11 2014

A320904 T(n, k) = binomial(2*n + 1 - k, k)*hypergeom([1, 1, -k], [1, 2*(n - k + 1)], -1), triangle read by rows, T(n, k) for n >= 0 and 0 <= k <= n.

Original entry on oeis.org

1, 1, 3, 1, 5, 7, 1, 7, 16, 15, 1, 9, 29, 42, 31, 1, 11, 46, 93, 99, 63, 1, 13, 67, 176, 256, 219, 127, 1, 15, 92, 299, 562, 638, 466, 255, 1, 17, 121, 470, 1093, 1586, 1486, 968, 511, 1, 19, 154, 697, 1941, 3473, 4096, 3302, 1981, 1023
Offset: 0

Views

Author

Peter Luschny, Oct 28 2018

Keywords

Examples

			Triangle starts:
[0] 1
[1] 1,  3
[2] 1,  5,   7
[3] 1,  7,  16,  15
[4] 1,  9,  29,  42,   31
[5] 1, 11,  46,  93,   99,   63
[6] 1, 13,  67, 176,  256,  219,  127
[7] 1, 15,  92, 299,  562,  638,  466, 255
[8] 1, 17, 121, 470, 1093, 1586, 1486, 968, 511
		

Crossrefs

Row sums are A105693(n-1).
Cf. A097750.

Programs

  • Maple
    T := (n, k) -> binomial(2*n + 1 - k, k)*hypergeom([1, 1, -k], [1, 2*(n-k+1)], -1):
    for n from 0 to 11 do seq(simplify(T(n, k)), k = 0..n) od;
  • Mathematica
    s={};For[n=0,n<19,n++,For[k=0,kDetlef Meya, Oct 03 2023 *)
Showing 1-3 of 3 results.