Sequence and first differences (A030124) together include all positive numbers exactly once.
1, 3, 7, 12, 18, 26, 35, 45, 56, 69, 83, 98, 114, 131, 150, 170, 191, 213, 236, 260, 285
1 seqfan posts
Sat Jan 17 21:14:44 CET 2009 [seqfan] Re: help needed in editing A139123