a positive two digit integer ab is a multiple of a + b - 1. How many such integers are there?
a=1;b=1;p=0; cycle:d=a*10+b;if(a*b%(a+b-1)==0, goto loop, goto next); loop:printd,", ",;p=p+1; next:b++;if(b<10, goto cycle, 0);b=1;a++;if(a<10, goto cycle, 0);print"Total = ",p
OUTPUT:
11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 21 , 31 , 34 , 41 , 43 , 49 , 51 , 56 , 61 , 65 , 71 , 78 , 81 , 87 , 91 , 94 , Total = 25 such integers.
