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.
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
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.
Links
- G. C. Greubel, Rows n=0..100 of triangle, flattened
Programs
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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;
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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 *)
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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
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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)]
Comments