i need a code of expression for the below number triangle?

Don't you want to try to solve your test questions yourself?

a!forEach(
  items: enumerate(5),
  expression: joinarray(
    5 - enumerate(5 - (5 - fv!index)),
    char(10)
  )
)

reverse(
a!forEach(
items: enumerate(5),
expression: joinarray(
rdrop(reverse(enumerate(5) + 1), fv!item)
)
)
)