A209984 Number of 2 X 2 matrices having all elements in {-n,...n} and determinant 2.

0, 4, 92, 156, 284, 412, 604, 796, 1052, 1244, 1628, 1948, 2204, 2588, 3164, 3420, 3932, 4444, 5020, 5596, 6108, 6492, 7452, 8156, 8668, 9308, 10460, 11036, 11804, 12700, 13468, 14428, 15452, 16092, 17628, 18396, 19164, 20316, 22044

Offset: 0

Author

Clark Kimberling, Mar 17 2012

Keywords

• nonn

Comments

See A210000 for a guide to related sequences.

Examples

			a(1) counts these matrices (in reduced notation):
(-1,-1,1,-1), (-1,1,-1,-1), (1,-1,1,1), (1,1,-1,1)
		

Links

• Chai Wah Wu, Table of n, a(n) for n = 0..10000

Crossrefs

Cf. A210000.

Programs

Mathematica

(See the Mathematica section at A209981.)