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 A348129 #23 Oct 07 2021 18:07:13 %S A348129 1,1,1,1,4,0,1,9,8,0,1,16,44,24,2,1,25,140,204,82,10,1,36,340,1024, %T A348129 982,248,4,1,49,700,3628,7002,4618,832,40,1,64,1288,10320,34568,46736, %U A348129 22708,3192,92,1,81,2184,25096,131248,310496,312956,119180,13848,352,1,100,3480,54400,412596,1535440,2716096,2119176,636524,56832,724 %N A348129 Number T(n,k) of ways to place k nonattacking queens on an n X n board; triangle T(n,k), n>=0, 0<=k<=n, read by rows. %e A348129 T(3,2) = 8: %e A348129 .-----. .-----. .-----. .-----. .-----. .-----. .-----. .-----. %e A348129 |Q . .| |Q . .| |. . Q| |. . Q| |. . .| |. Q .| |. Q .| |. . .| %e A348129 |. . Q| |. . .| |. . .| |Q . .| |Q . .| |. . .| |. . .| |. . Q| %e A348129 |. . .| |. Q .| |. Q .| |. . .| |. . Q| |. . Q| |Q . .| |Q . .| %e A348129 `-----´ `-----´ `-----´ `-----´ `-----´ `-----´ `-----´ `-----´. %e A348129 Triangle T(n,k) begins: %e A348129 1; %e A348129 1, 1; %e A348129 1, 4, 0; %e A348129 1, 9, 8, 0; %e A348129 1, 16, 44, 24, 2; %e A348129 1, 25, 140, 204, 82, 10; %e A348129 1, 36, 340, 1024, 982, 248, 4; %e A348129 1, 49, 700, 3628, 7002, 4618, 832, 40; %e A348129 1, 64, 1288, 10320, 34568, 46736, 22708, 3192, 92; %e A348129 1, 81, 2184, 25096, 131248, 310496, 312956, 119180, 13848, 352; %e A348129 ... %Y A348129 Columns k=0-8 give: A000012, A000290, A036464, A047659, A061994, A108792, A176186, A178721, A252593. %Y A348129 Main diagonal gives A000170. %Y A348129 Row sums give A287227. %Y A348129 T(2n,n) gives A348130. %Y A348129 Cf. A090642, A144084, A178717. %K A348129 nonn,tabl,hard %O A348129 0,5 %A A348129 _Alois P. Heinz_, Oct 01 2021