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.
%I A201635 #10 Mar 01 2019 08:04:19 %S A201635 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, %T A201635 1,6,22,62,148,314,610,1106,1,7,29,91,239,553,1163,2269,4166,1,8,37, %U A201635 128,367,920,2083,4352,8518,15792,1,9,46,174,541,1461,3544,7896 %N 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. %C A201635 Notation: If a sequence id is starred then the offset and/or some terms are different. Starred terms indicate the variance. %C A201635 Row sums: [A026641 ] [1, 1, 4, 13, 46, 166, 610] %C A201635 -- %C A201635 T(j+2, 2) [A000124*] [1*, 2 , 4, 7, 11, 16, 22] %C A201635 T(j+3, 3) [A003600*] [1*, 2*, 6, 13, 24, 40, 62] %C A201635 -- %C A201635 T(j , j) [A072547 ] [1, 0, 2, 6, 22, 80, 296] %C A201635 T(j+1, j) [A026641 ] [1, 1, 4, 13, 46, 166, 610] %C A201635 T(j+2, j) [A014300 ] [1, 2, 7, 24, 86, 314, 1163] %C A201635 T(j+3, j) [A014301*] [1, 3, 11, 40, 148, 553, 2083] %C A201635 T(j+4, j) [A172025 ] [1, 4, 16, 62, 239, 920, 3544] %C A201635 T(j+5, j) [A172061 ] [1, 5, 22, 91, 367, 1461, 5776] %C A201635 T(j+6, j) [A172062 ] [1, 6, 29, 128, 541, 2232, 9076] %C A201635 T(j+7, j) [A172063 ] [1, 7, 37, 174, 771, 3300, 13820] %C A201635 -- %C A201635 T(2j ,j) [Central ] [1, 1, 7, 40, 239, 1461, 9076] %C A201635 T(2j+1,j) [A183160 ] [1, 2, 11, 62, 367, 2232, 13820] %C A201635 T(2j+2,j) [ ] [1, 3, 16, 91, 541, 3300, 20476] %C A201635 T(2j+3,j) [A199033*] [1, 4, 22, 128, 771, 4744, 29618] %H A201635 G. C. Greubel, <a href="/A201635/b201635.txt">Rows n=0..100 of triangle, flattened</a> %e A201635 Triangle begins as: %e A201635 [n]|k-> %e A201635 [0] 1 %e A201635 [1] 1, 0 %e A201635 [2] 1, 1, 2 %e A201635 [3] 1, 2, 4, 6 %e A201635 [4] 1, 3, 7, 13, 22 %e A201635 [5] 1, 4, 11, 24, 46, 80 %e A201635 [6] 1, 5, 16, 40, 86, 166, 296 %e A201635 [7] 1, 6, 22, 62, 148, 314, 610, 1106. %p A201635 A201635 := proc(n,k) option remember; local j; %p A201635 if n=k then (-1)^n*add(binomial(-n,j), j=0..n) %p A201635 else add(A201635(n-1,j), j=0..k) fi end: %p A201635 for n from 0 to 7 do seq(A(n,k), k=0..n) od; %t A201635 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 *) %o A201635 (Sage) %o A201635 @CachedFunction %o A201635 def A201635(n, k): %o A201635 if n==k: return (-1)^n*add(binomial(-n, j) for j in (0..n)) %o A201635 return add(A201635(n-1, j) for j in (0..k)) %o A201635 for n in (0..7) : [A201635(n, k) for k in (0..n)] %o A201635 (PARI) %o A201635 {T(n,k) = if(k==n, (-1)^n*sum(j=0,n, binomial(-n,j)), sum(j=0,k, T(n-1,j)))}; %o A201635 for(n=0,10, for(k=0,n, print1(T(n,k), ", "))) \\ _G. C. Greubel_, Feb 27 2019 %K A201635 nonn,tabl %O A201635 0,6 %A A201635 _Peter Luschny_, Nov 14 2012