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

1, 5, 112, 7113, 745285, 90536348

Offset: 1

Author

Hugo Pfoertner at the suggestion of Markus Sigg, Feb 15 2022

Keywords

• nonn
• hard
• more

Examples

			a(2) = 5:
  [2, 1;
   1, 3]
.
a(3) = 112:
  [1, 5, 4;
   5, 3, 6;
   4, 6, 2]
.
a(4) = 7113:
  [ 3, 10,  4,  8;
   10,  5,  1,  6;
    4,  1,  7,  9;
    8,  6,  9,  2]
.
a(5) = 745285:
  [10, 12,  1,  4, 13;
   12,  6,  5, 15,  3;
    1,  5,  9, 11, 14;
    4, 15, 11,  7,  2;
   13,  3, 14,  2,  8]
.
a(6) = 90536348:
  [18,  1,  7, 14,  6, 15;
    1, 13,  5, 17,  8, 20;
    7,  5, 12,  2, 21, 16;
   14, 17,  2, 11, 19,  3;
    6,  8, 21, 19,  9,  4;
   15, 20, 16,  3,  4, 10]
		

Crossrefs

Cf. A000217, A085000, A351147, A351609.