Code

What is the purpose? Is this a test? Did you try enumerate()?

What is the actual logic behind this request?   You didn't explain how your output ("{2, 3, 4, 5}") actually relates to the input of "1".  I could write an expression rule hardcoded to output {2, 3, 4, 5} no matter what input value was given, and claim it satisfies this based on the information provided here.

a!foreach(
items:{1},
expression:fv!item+1+enumerate(4)
)

As has already been said, we need may more info. If you need the proceeding X number of integers after the input number the below will work. But this is really just a stab in the dark.

a!localVariables(
  local!inputNumber: 5,
  local!numberOfSubsequentIntegersToReturn: 4,
  1 + local!inputNumber + enumerate(local!numberOfSubsequentNumbersToReturn)
)

[mention:eb9a70f0b32a430e8819bff3623248f0:e9ed411860ed4f2ba0265705b8793d05]

While you post any query can you please try to be more specific with the use case so that it will be easy for other Appian users to provide better solutions catering to query more profoundly?

just trying to keep the community clean.