Build a mini API and a webpage that use it

I need and API on a three-based numerical settings and a key Input A : user give one positive integer "n" Input B : user can give zero to n-1 distinct integer, count distinct of theses inputs B are i Input C : user give one positive integer "j" from 1 to n-i Input D : key API How to call it, for instance ! You can improve ! [login to view URL] Real name of input given later Theses inputs generate a unique random combinaison of j distinct integer between the n integer after exclusion of the integer gaven in input B. Exemple 1: A 5 B none C 3 Examples of results : 5 2 3 or 3 5 2 or 1 2 3 or 3 2 1 or 5 4 2, etc... Example in the API : { "random":[ "5", "2", "3", ], "response_date_time":"aaaa-mm-ddThh:mm:ss+01:00" } Exemple 2: A 3 B 1 C 2 Results possibles : only 2 3 or 3 2 Exemple 3: A 6 B 2 3 6 C 2 Examples of results : 1 5 or 5 4 or 1 4 or 4 1... Exemple 4: A 15 B 0 C 5 Examples of results : 2 14 13 6 9, 5 9 8 4 3.... You also - built an online page on my website to use this API with a form (API key not visible) - offer to the user of the form the opportunity to send to his random combinaison to his mail - each API_id, random combinaison generate, date and email are saved in a database - built a simple page for developpers Here and example on another topic that I find to be inspiring : [login to view URL] Regards !