/* 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
)$

/* Routine that extracts from primes between 2 and 500, inclusive, the additive primes */
block(
    primes(2,500),
    sublist(%%,lambda([x],primep(apply("+",decompose(x))))));

/* Number of additive primes in the rank */
length(%);