Developing a Mac Application to generate numbers

Looking to develop an application to work on MAC that does the following: 1) allow me to enter PREFIX number. 2) determine the total number of digits in the generated numbers 8 ,7,4..... etc 3) Choosing 25,000 ( random numbers from the TOTAL numbers in the list) 4) Next time I open the software, the new RANDOM 25,000 should not include any of the old results. 5) The 25,000 random numbers should be saved in .VCF format (V card) Example: Prefix number +1234 Number of digits 7( 7 means that there will 9,999,999 total numbers) The list will be like : +12340000001 +12340000002 ........ +12349999999 The results in the output file will include RANDOM 25,000 numbers between +12340000000 TO +12349999999 The result then will be stored in Vcard --- To make sure you have read all details, please write "GURU" on the top of your bid. While I prefer that to be done in Java, I'm open to any other language that would worm on Mac