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 A353103 #16 Apr 29 2022 15:53:20 %S A353103 3,7,9,12,16,21,25,32,37 %N A353103 Solution to Forest of Numbers (Bosque de Números) puzzle for Opaque Rooks starting with numbers 1 and 2 for an n X n square grid (see Comments). %C A353103 Start with an n X n square grid. Each cell has neighbors horizontally and vertically. Place the numbers 1 and 2 anywhere. Now place the numbers 3, 4, ..., m in order, subject to the rule that when you place k, the sum of the numbers that a Chess Rook attack in the same row and column must equal k. Then a(n) is the maximum m that can be achieved. %H A353103 Rodolfo Kurchan, <a href="https://www.puzzlefun.online/problems">Puzzle Fun, Problems, Forest of Numbers</a> %e A353103 Solution for a(5) = 12 from Rodolfo Kurchan: %e A353103 +---+---+---+---+---+ %e A353103 | 1 | | | 4 | 3 | %e A353103 +---+---+---+---+---+ %e A353103 | 6 | | | | 5 | %e A353103 +---+---+---+---+---+ %e A353103 | | | | 11| 7 | %e A353103 +---+---+---+---+---+ %e A353103 | | | | | 9 | %e A353103 +---+---+---+---+---+ %e A353103 | 8 | 10| 12| | 2 | %e A353103 +---+---+---+---+---+ %e A353103 Solutions for a(2) to a(6) from Rodolfo Kurchan. %e A353103 Solutions for a(7) to a(10) from Giorgio Vecchi. %Y A353103 Cf. A350627, A352814, A353070, A353093. %K A353103 nonn,more %O A353103 2,1 %A A353103 _Rodolfo Kurchan_, Apr 23 2022