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A177862 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. 4

%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), 881-888.

%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

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Last modified July 4 15:25 EDT 2020. Contains 335448 sequences. (Running on oeis4.)