A210284 Number of 2 X 2 matrices with all elements in {0,1,...,n} and determinant n+1.

0, 0, 1, 11, 9, 42, 23, 81, 72, 126, 79, 273, 121, 268, 280, 416, 227, 624, 299, 761, 570, 690, 457, 1384, 672, 1004, 982, 1489, 769, 2108, 893, 1980, 1500, 1768, 1574, 3308, 1303, 2250, 2118, 3658, 1637, 4120, 1823, 3751, 3527, 3320

Offset

0,4

Comments

See A210000 for a guide to related sequences.

Links

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

Mathematica

a = 0; b = n; z1 = 45;
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}]   (* A210284 *)

Crossrefs

Cf. A210000.

Sequence in context: A196006 A196003 A072208 * A219746 A335854 A220664

Adjacent sequences: A210281 A210282 A210283 * A210285 A210286 A210287

Keyword

nonn

Author

Clark Kimberling, Mar 19 2012

Status

approved