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.

A101164 Triangle read by rows: Delannoy numbers minus binomial coefficients.

Original entry on oeis.org

0, 0, 0, 0, 1, 0, 0, 2, 2, 0, 0, 3, 7, 3, 0, 0, 4, 15, 15, 4, 0, 0, 5, 26, 43, 26, 5, 0, 0, 6, 40, 94, 94, 40, 6, 0, 0, 7, 57, 175, 251, 175, 57, 7, 0, 0, 8, 77, 293, 555, 555, 293, 77, 8, 0, 0, 9, 100, 455, 1079, 1431, 1079, 455, 100, 9, 0, 0, 10, 126, 668, 1911, 3191, 3191, 1911, 668, 126, 10, 0
Offset: 0

Views

Author

Reinhard Zumkeller, Dec 03 2004

Keywords

Examples

			Triangle begins as:
  0
  0, 0;
  0, 1,  0;
  0, 2,  2,   0;
  0, 3,  7,   3,   0;
  0, 4, 15,  15,   4,   0;
  0, 5, 26,  43,  26,   5,  0;
  0, 6, 40,  94,  94,  40,  6, 0;
  0, 7, 57, 175, 251, 175, 57, 7, 0;
		

Crossrefs

Programs

  • Haskell
    a101164 n k = a101164_tabl !! n !! k
    a101164_row n = a101164_tabl !! n
    a101164_tabl = zipWith (zipWith (-)) a008288_tabl a007318_tabl
    -- Reinhard Zumkeller, Jul 30 2013
    
  • Magma
    A101164:= func< n,k | (&+[Binomial(n-k,j)*Binomial(k,j)*2^j: j in [0..n-k]]) - Binomial(n,k) >;
    [A101164(n,k): k in [0..n], n in [0..12]]; // G. C. Greubel, Sep 17 2021
    
  • Mathematica
    T[n_, k_]:= Hypergeometric2F1[-k, k-n, 1, 2] - Binomial[n, k];
    Table[T[n, k], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Sep 17 2021 *)
  • Sage
    def T(n,k): return simplify(hypergeometric([-n+k, -k], [1], 2)) - binomial(n,k)
    flatten([[T(n,k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Sep 17 2021

Formula

T(n, k) = A008288(n, k) - binomial(n, k), 0<=k<=n, where binomial=A007318.
T(n,2) = A005449(n-2) for n>1;
T(n,3) = A101165(n-3) for n>2;
T(n,4) = A101166(n-4) for n>3;
Sum_{k=0..n} T(n, k) = A094706(n).
From G. C. Greubel, Sep 17 2021: (Start)
T(n, k) = Sum_{j=0..n-k} binomial(n-k, j)*binomial(k, j)*2^j - binomial(n,k).
T(n, 1) = n-1, n > 0. (End)