A232496 Triangle read by rows: T(n,k) (n >= 2, 1 <= k <= n-1) = Euclidean distance degree of variety of n X n matrices of rank <= k.

4, 13, 13, 40, 122, 40, 121, 1042, 1042, 121, 364, 8683, 23544, 8683, 364, 1093, 72271, 510835, 510835, 72271, 1093

Offset

2,1

Comments

Column 1 appears to follow the recurrence T(n, 1) = 3*T(n-1, 1) + 1 (A003462, all ones in base 3). - Georg Fischer, Mar 05 2020

Links

Table of n, a(n) for n=2..22.

J. Draisma, E. Horobet, G. Ottaviani, B. Sturmfels and R. K. Thomas, The Euclidean distance degree of an algebraic variety, arXiv preprint arXiv: 1309.0049 [math.AG], 2013-2014, p. 24.

Example

Triangle begins:
     4;
    13,    13;
    40,   122,     40;
   121,  1042,   1042,    121;
   364,  8683,  23544,   8683,   364;
  1093, 72271, 510835, 510835, 72271, 1093;
  ...

Crossrefs

Cf. A003462.

Sequence in context: A168401 A370644 A081738 * A239256 A043049 A135465

Adjacent sequences: A232493 A232494 A232495 * A232497 A232498 A232499

Keyword

nonn,tabl,more

Author

N. J. A. Sloane, Dec 03 2013

Status

approved