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A351148 a(n) is the maximal determinant of a symmetric n X n matrix using the integers 1 to n*(n+1)/2.

%I A351148 #10 Aug 17 2023 08:16:52
%S A351148 1,5,112,7113,745285,90536348
%N A351148 a(n) is the maximal determinant of a symmetric n X n matrix using the integers 1 to n*(n+1)/2.
%e A351148 a(2) = 5:
%e A351148   [2, 1;
%e A351148    1, 3]
%e A351148 .
%e A351148 a(3) = 112:
%e A351148   [1, 5, 4;
%e A351148    5, 3, 6;
%e A351148    4, 6, 2]
%e A351148 .
%e A351148 a(4) = 7113:
%e A351148   [ 3, 10,  4,  8;
%e A351148    10,  5,  1,  6;
%e A351148     4,  1,  7,  9;
%e A351148     8,  6,  9,  2]
%e A351148 .
%e A351148 a(5) = 745285:
%e A351148   [10, 12,  1,  4, 13;
%e A351148    12,  6,  5, 15,  3;
%e A351148     1,  5,  9, 11, 14;
%e A351148     4, 15, 11,  7,  2;
%e A351148    13,  3, 14,  2,  8]
%e A351148 .
%e A351148 a(6) = 90536348:
%e A351148   [18,  1,  7, 14,  6, 15;
%e A351148     1, 13,  5, 17,  8, 20;
%e A351148     7,  5, 12,  2, 21, 16;
%e A351148    14, 17,  2, 11, 19,  3;
%e A351148     6,  8, 21, 19,  9,  4;
%e A351148    15, 20, 16,  3,  4, 10]
%Y A351148 Cf. A000217, A085000, A351147, A351609.
%K A351148 nonn,hard,more
%O A351148 1,2
%A A351148 _Hugo Pfoertner_ at the suggestion of _Markus Sigg_, Feb 15 2022