I've updated A005670 based on the recent discussions, by adding comments, examples and references. But I did not change the list of exact values given there, which are: %S A005670 1,4,6,7,8,9,9,10,10,11,11,11,11,12,12,12,12,13,13,13 or in other words: n a(n) 1 1 2 4 3 6 4 7 5 8 6 9 7 9 8 10 9 10 10 11 11 11 12 11 13 11 14 12 15 12 16 12 17 12 18 13 19 13 20 13 Could someone please clarify just what the known exact values are? Ed? John? Thanks! Neil