Number of pairs of 2 X 2 matrices over Z/nZ that do not commute.

Terms

a(0) =0a(1) =168a(2) =5616a(3) =59136a(4) =372000a(5) =1596456a(6) =5630688a(7) =16343040a(8) =42305328a(9) =98361000a(10) =212427600a(11) =423933696a(12) =810534816a(13) =1463987112a(14) =2545290000a(15) =4266393600a(16) =6950204928a(17) =10954717992a(18) =16934047920a(19) =25480800000a(20) =37696122576a(21) =54705920808a(22) =78156525216a(23) =109665017856a(24) =152287500000