create or replace function first_forward_diff(l) as (
  with cte as (select unnest(l) as i, unnest(range(0,length(l))) as ix),
  forward as (select ix, (lead(i) over () - i) as f from cte),
  agg as (select array_agg(f order by ix) from forward)
  select list_filter((from agg limit 1), x -> x is not null)
);

create or replace function ndiff_table(lst, mx) as table (
  with recursive cte as (
    select 0 as n, lst as diff
    union all
    select n+1, first_forward_diff(diff) as diff
    from cte
    where n < mx and diff != [] )
  select n as order, diff from cte
);