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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A201635 Triangle formed by T(n,n) = (-1)^n*Sum_{j=0..n} C(-n,j), T(n,k) = Sum_{j=0..k} T(n-1,j) for k=0..n-1, and n>=0, read by rows.

Original entry on oeis.org

1, 1, 0, 1, 1, 2, 1, 2, 4, 6, 1, 3, 7, 13, 22, 1, 4, 11, 24, 46, 80, 1, 5, 16, 40, 86, 166, 296, 1, 6, 22, 62, 148, 314, 610, 1106, 1, 7, 29, 91, 239, 553, 1163, 2269, 4166, 1, 8, 37, 128, 367, 920, 2083, 4352, 8518, 15792, 1, 9, 46, 174, 541, 1461, 3544, 7896
Offset: 0

Views

Author

Peter Luschny, Nov 14 2012

Keywords

Comments

Notation: If a sequence id is starred then the offset and/or some terms are different. Starred terms indicate the variance.
Row sums: [A026641 ] [1, 1, 4, 13, 46, 166, 610]
--
T(j+2, 2) [A000124*] [1*, 2 , 4, 7, 11, 16, 22]
T(j+3, 3) [A003600*] [1*, 2*, 6, 13, 24, 40, 62]
--
T(j , j) [A072547 ] [1, 0, 2, 6, 22, 80, 296]
T(j+1, j) [A026641 ] [1, 1, 4, 13, 46, 166, 610]
T(j+2, j) [A014300 ] [1, 2, 7, 24, 86, 314, 1163]
T(j+3, j) [A014301*] [1, 3, 11, 40, 148, 553, 2083]
T(j+4, j) [A172025 ] [1, 4, 16, 62, 239, 920, 3544]
T(j+5, j) [A172061 ] [1, 5, 22, 91, 367, 1461, 5776]
T(j+6, j) [A172062 ] [1, 6, 29, 128, 541, 2232, 9076]
T(j+7, j) [A172063 ] [1, 7, 37, 174, 771, 3300, 13820]
--
T(2j ,j) [Central ] [1, 1, 7, 40, 239, 1461, 9076]
T(2j+1,j) [A183160 ] [1, 2, 11, 62, 367, 2232, 13820]
T(2j+2,j) [ ] [1, 3, 16, 91, 541, 3300, 20476]
T(2j+3,j) [A199033*] [1, 4, 22, 128, 771, 4744, 29618]

Examples

			Triangle begins as:
[n]|k->
[0] 1
[1] 1, 0
[2] 1, 1,  2
[3] 1, 2,  4,  6
[4] 1, 3,  7, 13,  22
[5] 1, 4, 11, 24,  46,  80
[6] 1, 5, 16, 40,  86, 166, 296
[7] 1, 6, 22, 62, 148, 314, 610, 1106.
		

Programs

  • Maple
    A201635 := proc(n,k) option remember; local j;
    if n=k then (-1)^n*add(binomial(-n,j), j=0..n)
    else add(A201635(n-1,j), j=0..k) fi end:
    for n from 0 to 7 do seq(A(n,k), k=0..n) od;
  • Mathematica
    T[n_, k_]:= T[n, k]= If[k==n, (-1)^n*Sum[Binomial[-n, j], {j, 0, n}], Sum[T[n-1, j], {j, 0, k}]]; Table[T[n, k], {n,0,10}, {k,0,n}]//Flatten (* G. C. Greubel, Feb 27 2019 *)
  • PARI
    {T(n,k) = if(k==n, (-1)^n*sum(j=0,n, binomial(-n,j)), sum(j=0,k, T(n-1,j)))};
    for(n=0,10, for(k=0,n, print1(T(n,k), ", "))) \\ G. C. Greubel, Feb 27 2019
  • Sage
    @CachedFunction
    def A201635(n, k):
        if n==k: return (-1)^n*add(binomial(-n, j) for j in (0..n))
        return add(A201635(n-1, j) for j in (0..k))
    for n in (0..7) : [A201635(n, k) for k in (0..n)]
    
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