A211145 Number of 2 X 2 matrices having all terms in {-n,...,0,..,n} and permanent=trace.

1, 19, 60, 116, 196, 292, 404, 548, 708, 868, 1060, 1284, 1524, 1796, 2052, 2292, 2612, 2980, 3348, 3748, 4116, 4452, 4884, 5380, 5844, 6324, 6820, 7300, 7860, 8468, 9060, 9732, 10388, 10964, 11572, 12180, 12852, 13668, 14436, 15092

Offset: 0

Author

Clark Kimberling, Apr 03 2012

Keywords

• nonn

Comments

For a guide to related sequences, see A210000.

Links

• David Radcliffe, Table of n, a(n) for n = 0..2000

Crossrefs

Cf. A210000.

Programs

Mathematica

a = -n; b = n; z1 = 40;
t[n_] := t[n] = Flatten[Table[w + z - 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, 0], {n, 0, z1}]   (* A211145 *)
(1/4) Table[c[n, n], {n, 2, z1}] (* integers *)