These define three classifications of positive integers based on their   proper divisors.

Let   P(n)   be the sum of the proper divisors of   n   where the proper divisors are all positive divisors of   n   other than   n   itself.

   if    P(n) <  n    then  n  is classed as  deficient  (OEIS A005100).
   if    P(n) == n    then  n  is classed as  perfect    (OEIS A000396).
   if    P(n) >  n    then  n  is classed as  abundant   (OEIS A005101).



Example

6   has proper divisors of   1,   2,   and   3.

1 + 2 + 3 = 6,   so   6   is classed as a perfect number.



Task

Calculate how many of the integers   1   to   20,000   (inclusive) are in each of the three classes.

Show the results here.



Related tasks

   Aliquot sequence classifications.   (The whole series from which this task is a subset.)
   Proper divisors
   Amicable pairs


 
# Abundant, deficient and perfect number classifications. 12/10/16 aev
require(numbers);
propdivcls <- function(n) {
  V <- sapply(1:n, Sigma, proper = TRUE);
  c1 <- c2 <- c3 <- 0;
  for(i in 1:n){
    if(V[i]<i){c1 = c1 +1} else if(V[i]==i){c2 = c2 +1} else{c3 = c3 +1}
  } 
  cat(" *** Between 1 and ", n, ":\n");
  cat("   * ", c1, "deficient numbers\n");
  cat("   * ", c2, "perfect numbers\n");
  cat("   * ", c3, "abundant numbers\n");
}
propdivcls(20000);
 