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 1-2 of 2 results.

A099092 Riordan array (1,2+4x).

Original entry on oeis.org

1, 0, 2, 0, 4, 4, 0, 0, 16, 8, 0, 0, 16, 48, 16, 0, 0, 0, 96, 128, 32, 0, 0, 0, 64, 384, 320, 64, 0, 0, 0, 0, 512, 1280, 768, 128, 0, 0, 0, 0, 256, 2560, 3840, 1792, 256, 0, 0, 0, 0, 0, 2560, 10240, 10752, 4096, 512, 0, 0, 0, 0, 0, 1024, 15360, 35840, 28672, 9216, 1024, 0, 0, 0
Offset: 0

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Author

Paul Barry, Sep 25 2004

Keywords

Comments

Row sums are A063727. Diagonal sums are A052907.
The Riordan array (1, s+tx) defines T(n,k) = binomial(k,n-k)*s^k*(t/s)^(n-k). The row sums satisfy a(n) = s*a(n-1) + t*a(n-2) and the diagonal sums satisfy a(n) = s*a(n-2) + t*a(n-3).

Examples

			Rows begin
  {1},
  {0,  2},
  {0,  4,  4},
  {0,  0, 16,  8},
  {0,  0, 16, 48, 16}, ...
		

Crossrefs

Formula

Number triangle T(n,k) = binomial(k, n-k)*2^n; columns have g.f. (2x+4x^2)^k.
T(n,k) = A113953(n,k)*2^k = A026729(n,k)*2^n. - Philippe Deléham, Dec 11 2008

A137337 T(i,j) = (-1)^(i+j)*(i+1)*binomial(i,j)*2^(i-j)*4^j.

Original entry on oeis.org

1, -4, 8, 12, -48, 48, -32, 192, -384, 256, 80, -640, 1920, -2560, 1280, -192, 1920, -7680, 15360, -15360, 6144, 448, -5376, 26880, -71680, 107520, -86016, 28672, -1024, 14336, -86016, 286720, -573440, 688128, -458752, 131072, 2304, -36864, 258048, -1032192, 2580480, -4128768, 4128768, -2359296, 589824
Offset: 0

Views

Author

Roger L. Bagula, Apr 07 2008

Keywords

Comments

Apart from signs, row i equals (i+1) times row i of A038210. - Joerg Arndt, Aug 07 2020

Examples

			Triangle starts:
1,
-4, 8,
12, -48, 48,
-32, 192, -384, 256,
80, -640, 1920, -2560, 1280,
-192, 1920, -7680, 15360, -15360, 6144,
448, -5376, 26880, -71680, 107520, -86016, 28672,
-1024, 14336, -86016, 286720, -573440, 688128, -458752, 131072,...
		

Programs

  • PARI
    T(i,j) = (-1)^(i+j)*(i+1)*binomial(i,j)*2^(i-j)*4^j;
    for(i=0,10,for(j=0,i,print1(T(i,j),", "));print()); \\ Joerg Arndt, Aug 07 2020

Extensions

Corrected and edited by Joerg Arndt, Aug 07 2020
Definition corrected to match terms by Georg Fischer, Apr 28 2022
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