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 A351609 #11 Feb 18 2022 08:06:47 %S A351609 1,1,7,152,7113,745285,94974369 %N A351609 Maximal absolute value of the determinant of an n X n symmetric matrix using the integers 1 to n*(n + 1)/2. %C A351609 Upper bounds for the next terms can be found by considering all possibilities of choosing matrix entries on the diagonal and applying Gasper's determinant theorem (see references in A085000): a(7) <= 22475584128, a(8) <= 6634478203404, a(9) <= 2647044512044258. - _Hugo Pfoertner_, Feb 18 2022 %F A351609 a(n) = max(abs(A351147(n)), A351148(n)). - _Hugo Pfoertner_, Feb 16 2022 %e A351609 a(3) = 152: %e A351609 2 4 6 %e A351609 4 5 1 %e A351609 6 1 3 %e A351609 a(4) = 7113: %e A351609 2 6 8 9 %e A351609 6 5 10 1 %e A351609 8 10 3 4 %e A351609 9 1 4 7 %Y A351609 Cf. A000217, A351147, A351148, A351153. %Y A351609 Cf. A085000, A180128, A350931, A350933, A350954, A350956. %K A351609 nonn,hard,more %O A351609 0,3 %A A351609 _Stefano Spezia_, Feb 14 2022 %E A351609 a(5)-a(6) from _Hugo Pfoertner_, Feb 16 2022