Hi Guys! I hope all of you are fine :) Maybe someone can tell me here how can I find, with Wolfram Alpha or Mathematica, numbers they have the same sum of digits? For Example: 9999 = 36, now I need a method (or a search criterion for Wolfram Alpha) to find quickly other numbers with the same cross sum. I hope anyone can help me here. Kind regards and best wishes.

Hi Henrik & Daniel! Thank you both very much for your time and for the valuable contributions to my question, i really appreciate that! I wish you both also all the best! I am sure i will need these solutions once upon a time as well, and many others (beginners) like me, e.g to understand better the logic behind the wolfram language, but at moment, the method from @Rapsi works perfect for me, it is simple and fast enough, generates me in few minutes a long list (up to 111111111) with the numbers i need. Nevertheless, thanks again, and have a wonderfull day. Best regards.

I guess in this context the function `IntegerPartitions` should at least be mentioned. It could be used here like so: numberList[n_] := Select[IntegerPartitions[n], Max[#] < 10 &] and from this calculate the numbers, e.g.: nl = numberList[12]; FromDigits /@ Flatten[Permutations /@ nl, 1] I cannot imagine to calculate all those numbers for non small `n`, because the length of this list goes approximately like 0.50398 E^(0.692161 n), which e.g. for `n=36` gives 3.34258*10^10 different numbers. Or am I misunderstanding the question?

Hi Raspi, yeah, that's it! I don't know how to thank you. I wish you all the best and God's blessing. Thank you very much! Have a wonderful day. Best regards.

Find numbers with the same cross sum (sum of digits)?