Problem Statement

Two integers

N

{\displaystyle N}

and

M

{\displaystyle M}

are said to be amicable pairs if

N ≠ M

{\displaystyle N\neq M}

and the sum of the proper divisors of

N

{\displaystyle N}

(

s u m

(

p r o p D i v s

( N ) )

{\displaystyle \mathrm {sum} (\mathrm {propDivs} (N))}

)

= M

{\displaystyle =M}

as well as

s u m

(

p r o p D i v s

( M ) )

N

{\displaystyle \mathrm {sum} (\mathrm {propDivs} (M))=N}

.

1184 and 1210 are an amicable pair, with proper divisors:

Calculate and show here the Amicable pairs below 20,000; (there are eight).

Let's start with the solution:

10 M=20000
20 I=1
30 :I)=1
40 I=I+1
50 #=M>I*30
60 I=2
70 J=I+I
80 :J)=:J)+I
90 J=J+I
100 #=M>J*80
110 I=I+1
120 #=(M/2)>I*70
130 I=1
140 J=:I)
150 #=(I
160 I=I+1
170 #=M>I*140
180 #=999
190 ?=I
200 $=9
210 ?=J
220 ?=""
230 #=!