/* Function that returns a list of digits given a nonnegative integer */
decompose(num) := block([digits, remainder],
  digits: [],
  while num > 0 do
   (remainder: mod(num, 10),
    digits: cons(remainder, digits),
    num: floor(num/10)),
  digits
)$

/* Test case */
block(babbage_param:269696,i:isqrt(babbage_param)+1,cache_babbage:decompose(babbage_param),
    while rest(decompose(i^2),(length(decompose(i^2))-6))#cache_babbage do i:i+2,
    i);