

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.


3



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, 21, 22, 22
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

0,2


LINKS

Table of n, a(n) for n=0..29.
O. A. Ivanov, On the number of regions into which n straight lines divide the plane, Amer. Math. Monthly, 117 (2010), 881888.


MAPLE

Triangle begins:
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 21 22 22
...


CROSSREFS

A000124, A055503, and A263883 are subsequences.
Sequence in context: A218443 A205787 A072455 * A066981 A130043 A089266
Adjacent sequences: A177859 A177860 A177861 * A177863 A177864 A177865


KEYWORD

nonn,tabf,more


AUTHOR

N. J. A. Sloane, Dec 18 2010


STATUS

approved



