login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A049008 Greatest possible number of right angles that can occur as interior angles in a planar n-gon. 0
1, 4, 3, 5, 5, 6, 7, 7, 8, 9, 9, 10, 11, 11, 12, 13, 13, 14, 15, 15, 16, 17, 17, 18, 19, 19, 20, 21, 21, 22, 23, 23, 24, 25, 25, 26, 27, 27, 28, 29, 29, 30, 31, 31, 32, 33, 33, 34, 35, 35, 36, 37, 37, 38, 39, 39, 40, 41, 41, 42, 43, 43, 44, 45, 45, 46, 47, 47, 48, 49, 49, 50 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,2

COMMENTS

Reflex angles (e.g. 270 degrees) are not considered right angles. From a(6) on, this duplicates A004396 from its eighth term.

LINKS

Table of n, a(n) for n=3..74.

FORMULA

a(3) = 1; a(4) = 4; a(5) = 3; a(3*k+3) = 2*k+3; a(3*k+4) = 2*k+3; a(3*k+5) = 2*k+4 where k starts from 1 OR a(n) is the greatest integer less than 2/3*(n+2) where n starts from 6.

EXAMPLE

a(3) = 1 because you can only have one right angle in a triangle; a(4) = 4 as in a rectangular quadrilateral; a(100) = 67 etc.

CROSSREFS

Cf. A004396.

Sequence in context: A024688 A024477 A270649 * A280023 A170816 A336067

Adjacent sequences:  A049005 A049006 A049007 * A049009 A049010 A049011

KEYWORD

easy,nonn

AUTHOR

Deepak R. N (deepak_rama(AT)bigfoot.com)

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 19 12:02 EDT 2021. Contains 345128 sequences. (Running on oeis4.)