%I
%S 1,2,3,4,4,6,7,5,8,9,10,11,6,10,12,13,14,15,16,7,12,15,16,17,18,19,20,
%T 21,22
%N Irregular triangle read by rows in which row n (n>=0) is a list of the numbers of different regions into which n lines can divide the plane.
%H O. A. Ivanov, <a href="http://www.jstor.org/stable/10.4169/000298910x523362">On the number of regions into which n straight lines divide the plane</a>, Amer. Math. Monthly, 117 (2010), 881888.
%e Triangle begins:
%e 1
%e 2
%e 3 4
%e 4 6 7
%e 5 8 9 10 11
%e 6 10 12 13 14 15 16
%e 7 12 15 16 17 18 19 20 21 22
%e ...
%Y A000124, A055503, and A263883 are subsequences.
%K nonn,tabf,more
%O 0,2
%A _N. J. A. Sloane_, Dec 18 2010
%E Duplicate term 22 removed on row n=6 and example fixed by _Luc Rousseau_, Feb 25 2019
