> Example for A=10: > 10--> 1,10,2,5 dig.sum=9 > 9--> 1,9,3 dig.sum=13 > 13--> 1,13 dig.sum=14 I think the dig.sum=5 on that last one but it does indeed end at 15: 10, 9, 13, 5, 6, 12, 19, 11, 3, 4, 7, 8, 15. Is there any sink other than 15 for starting numbers > 1 ?