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 A211798 #21 Sep 11 2022 00:45:33
%S A211798 2,12,1,36,7,1,80,23,7,1,150,54,22,7,1,252,103,51,22,7,1,392,175,97,
%T A211798 50,22,7,1,576,276,164,95,50,22,7,1,810,409,258,162,95,50,22,7,1,1100,
%U A211798 579,382,254,161,95,50,22,7,1,1452,791,541,375,253,161,95,50,22
%N A211798 R(k,n) = Sum_{y=1..n} Sum_{x=1..n} floor((x^k + y^k)^(1/k)), square array read by descending antidiagonals.
%F A211798 R(k,n) = Sum_{y=1..n} Sum_{x=1..n} floor((x^k + y^k)^(1/k)).
%e A211798 Northwest corner:
%e A211798 2 12 36 80 150 252 392
%e A211798 1 7 23 54 103 175 276
%e A211798 1 7 22 51 97 164 258
%e A211798 1 7 22 50 95 162 254
%e A211798 1 7 22 50 95 161 254
%e A211798 1 7 22 50 95 161 253
%t A211798 f[x_, y_, k_] := f[x, y, k] = Floor[(x^k + y^k)^(1/k)]
%t A211798 t[k_, n_] := Sum[Sum[f[x, y, k], {x, 1, n}], {y, 1, n}]
%t A211798 Table[t[1, n], {n, 1, 45}] (* 2*A002411 *)
%t A211798 Table[t[2, n], {n, 1, 45}] (* A211791 *)
%t A211798 Table[t[3, n], {n, 1, 45}] (* A211792 *)
%t A211798 TableForm[Table[t[k, n], {k, 1, 12},
%t A211798 {n, 1, 16}]] (* A211798 *)
%t A211798 Flatten[Table[t[k, n - k + 1], {n, 1, 12}, {k, 1, n}]]
%Y A211798 Cf. A002411 ((1/2) * row 1), A002412 (limiting row), A211791 (row 2), A211792 (row 3).
%K A211798 nonn,tabl
%O A211798 1,1
%A A211798 _Clark Kimberling_, Apr 26 2012
%E A211798 Definition changed by _Georg Fischer_, Sep 10 2022