posted by rohit .
Find the sum of all 3-digit positive numbers N that satisfy the condition that the digit sum of N is 3 times the digit sum of N+3.
Details and assumptions
The digit sum of a number is the sum of all its digits. For example, 1123 has a digit sum of 1+1+2+3=7.
The number 12=012 is a 2-digit number, not a 3-digit number.