A211141 Number of 2 X 2 matrices having all terms in {-n,...,0,...,n} and determinant n-1.

0, 33, 52, 156, 240, 492, 472, 1072, 832, 1612, 1540, 2408, 1680, 4144, 2296, 4064, 4352, 5900, 3592, 8236, 4464, 9544, 7712, 9168, 6208, 15984, 8812, 12232, 11968, 17504, 9464, 23712, 10976, 21772, 17440, 19960

Offset: 0

Author

Clark Kimberling, Apr 02 2012

Keywords

• nonn

Comments

For a guide to related sequences, see A210000.

Links

• Chai Wah Wu, Table of n, a(n) for n = 0..3000

Crossrefs

Cf. A210000.

Programs

Mathematica

a = -n; b = n; z1 = 35;
t[n_] := t[n] = Flatten[Table[w*z - x*y, {w, a, b}, {x, a, b}, {y, a, b}, {z, a, b}]]
c[n_, k_] := c[n, k] = Count[t[n], k]
Table[c[n, n - 1], {n, 0, z1}]  (* A211141 *)