Some of the accepted formats:

d6
or1d6
(A 6 sided die) 
2d6
(Two 6 sided dice) 
1d6+4
(Roll a 6 sided dice and add 4 to the result) 
2d10*4+1d20
(Roll two 10 sided dice multiply by four, and roll one 20 sided die) 
2d10+4+2d20dl1
(Roll two 10 sided dice add four, and roll two 20 sided die, taking away the lowest of the two) 
(2d10+4)*2
(Parenthesis to specify order of operations) 
d%
(A percentile die  equivalent tod100
) 
dF
ordF.2
(A standard fudge dice  2 thirds of each symbol) 
dF.1
(A nonstandard fudge dice  1 positive, 1 negative, 4 blank) 
2d6!
(Exploding dice  two 6 sided die, rolling again for each roll of the maximum value) 
2d6!!
(Exploding & compounding dice  like exploding, but adding together into single roll) 
2d6!p
(Penetrating dice  like exploding, but subtract 1 from each consecutive roll) 
2d6!!p
(Penetrating & compounding dice  like exploding & compounding, but subtract 1 from each consecutive roll) 
2d6!>=4
(Exploding dice, but only if you roll a 4 or greater  Also usable with compounding and penetrating dice) 
2d6>4f<=3
(Dice pool  anything greater than a 4 is a success, less than or equal to 3 is a fail. Count the number of successes, minus failures, as the total) 
floor(2d6/3)
,round(2d6/3)
,ceil(2d6/3)
(Rounding functions)
Arithmetic operators can be used: +
, 
, *
,
/
,
^
, %
Comparative operators can be used for compare points: =
, <
,
>
,
<=
, >=
, !=