Numbers of the form 6xy +- x +- y, where x, y are positive integers.
4, 6, 8, 9, 11, 13, 14, 15, 16, 19, 20, 21, 22, 24, 26, 27, 28, 29, 31, 34, 35, 36, 37, 39
1 seqfan posts
Mon Mar 1 15:17:36 CET 2010 [seqfan] Re: Exercises in what? Logic, English, or Writing?