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A351147 a(n) is the minimal determinant of a symmetric n X n matrix using the integers 1 to n*(n+1)/2.

%I A351147 #10 Aug 17 2023 08:16:46
%S A351147 1,-7,-152,-6276,-550010,-94974369
%N A351147 a(n) is the minimal determinant of a symmetric n X n matrix using the integers 1 to n*(n+1)/2.
%e A351147 a(2) = -7:
%e A351147   [1, 3;
%e A351147    3, 2]
%e A351147 .
%e A351147 a(3) = -152:
%e A351147   [5, 4, 1;
%e A351147    4, 2, 6;
%e A351147    1, 6, 3]
%e A351147 .
%e A351147 a(4) = -6276:
%e A351147   [9,  5,  2,  4;
%e A351147    5,  6, 10,  1;
%e A351147    2, 10,  3,  7;
%e A351147    4,  1,  7,  8]
%e A351147 .
%e A351147 a(5) = -550010:
%e A351147   [ 3, 14,  7, 13,  9;
%e A351147    14,  8,  1, 12,  4;
%e A351147     7,  1,  6, 10, 15;
%e A351147    13, 12, 10,  2, 11;
%e A351147     9,  4, 15, 11,  5]
%e A351147 .
%e A351147 a(6) = -94974369:
%e A351147   [ 5, 14,  7, 11, 21, 17;
%e A351147    14, 12, 19,  3, 16,  1;
%e A351147     7, 19, 13, 18,  2,  6;
%e A351147    11,  3, 18, 10,  4, 20;
%e A351147    21, 16,  2,  4,  9, 15;
%e A351147    17,  1,  6, 20, 15,  8]
%Y A351147 Cf. A000217, A085000, A351148, A351609.
%K A351147 sign,hard,more
%O A351147 1,2
%A A351147 _Hugo Pfoertner_ at the suggestion of _Markus Sigg_, Feb 15 2022