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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. 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), 881-888.

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

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Last modified May 28 20:12 EDT 2017. Contains 287241 sequences.