Texas Instruments TI-83 PLUS - Manual (Page 96)

TI-83 Plus Math, Angle, and Test Operations 93
With each rand execution, the TI-83 Plus generates the same random-
number sequence for a given seed value. The TI-83 Plus factory-set
seed value for rand is 0 . To generate a different random-number
sequence, store any nonzero seed value to rand . To restore the factory-
set seed value, store 0 to rand or reset the defaults (Chapter 18).
Note: The seed value also affects randInt( , randNorm( , and randBin( instructions.
nPr, nCr
nPr (number of permutations) returns the number of permutations of items
taken number at a time. items and number must be nonnegative integers.
Both items and number can be lists.
items nPr number
nCr (number of combinations) returns the number of combinations of
items taken number at a time. items and number must be nonnegative
integers. Both items and number can be lists.