Material true color dxf code help

[royboy666]

Here is a partial entity listing for a material whos RGB color is r249 g150 b134:

((-1 . <Entity name: 7ef0b498>) (0 . "MATERIAL") (5 . "173") (102 .
"{ACAD_XDICTIONARY") (360 . <Entity name: 7ef0b4a0>) (102 . "}") (102 .
"{ACAD_REACTORS") (330 . <Entity name: 7ef09e10>) (102 . "}") (330 . <Entity
name: 7ef09e10>) (100 . "AcDbMaterial") (1 . "template") (2 . "") (70 . 1) (40
. 1.0) (90 . -1023830394) (71 . 1) (41 . 1.0) (91 . -1023830394) (42 . 1.0) (72
. 0) (3 . "") (73 . 2) (74 . 1) (75 . 1) (43 . 1.0) (43 . 0.0) (43 . 0.0) (43 .
0.0) (43 . 0.0) (43 . 1.0) (43 . 0.0) (43 . 0.0) (43 . 0.0) (43 . 0.0) (43 .
1.0) (43 . 0.0) (43 . 0.0) (43 . 0.0) (43 . 0.0) (43 . 1.0) (44 . 0.1) (76 . 1)
(45 . 1.0) (92 . -1028609617) (46 . 1.0) (77 . 0) (4 . "") (78 . 2) (79 . 1)

90 is ambient, 91 diffuse, 92 specular.Ambient & diffuse are same rgb value noted above.

The 420 value via the acad_truecolordlg function is (420 . 16356998).

I am creating a utility that creates materials from the command prompt via lisp, how in the world do they figure NEGATIVE 1 billion (1023830394) to represent this true color value? I need sustitute this info but I have no idea or formula to get the 420 true value code to this number. Any help ?

Thanks