login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A176360 a(n) = quadrant of unit circle corresponding to n radians. 0
1, 2, 2, 3, 4, 4, 1, 2, 2, 3, 4, 4, 1, 1, 2, 3, 3, 4, 1, 1, 2, 3, 3, 4, 4, 1, 2, 2, 3, 4, 4, 1, 2, 2, 3, 3, 4, 1, 1, 2, 3, 3, 4, 1, 1, 2, 2, 3, 4, 4, 1, 2, 2, 3, 4, 4, 1, 1, 2, 3, 3, 4, 1, 1, 2, 3, 3, 4, 4, 1, 2, 2, 3, 4, 4, 1, 2, 2, 3, 3, 4, 1, 1, 2, 3, 3, 4, 1, 1, 2, 2, 3, 4, 4, 1, 2, 2, 3, 4, 4, 1, 1, 2, 3, 3 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Radians are the natural measure of angle. Quadrants (1 through 4) determine the signs of (x,y); of (cos x, sin x); and are ubiquitous.

Thereby it is "interesting" to consider which quadrant contains successively larger integer radian measure.

LINKS

Table of n, a(n) for n=1..105.

FORMULA

a(n) = 1 + {floor [2*n/Pi] modulo(4)}. - Adam Helman, Apr 20 2010

EXAMPLE

a(11) is very nearly 7 quadrants as Pi is nearly exactly 22/7.

Indeed, 11 radians lies just 4.4 milliradian (0.25 degree) within the 4th quadrant.

PROG

From Adam Helman, Apr 20 2010: (Start)

(Other) # a(n) = 1 + {floor [2*n/pi] modulo(4)}

# Ruby code by Andy Martin

# Overkill here, 4 places properly gives first 200 terms.

t = 2000000000000000000000000000000000000000000000000000000000000000000

pi = 3141592653589793238462643383279502884197169399375105820974944592307

(1..200).each{ |n| print "#{1 + ((n*t)/pi)%4}, "}

print "\b \n"

(End)

CROSSREFS

Sequence in context: A171830 A071506 A125920 * A185068 A078664 A325954

Adjacent sequences:  A176357 A176358 A176359 * A176361 A176362 A176363

KEYWORD

nonn,easy

AUTHOR

Adam Helman, Apr 15 2010, Apr 20 2010

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 September 21 12:35 EDT 2019. Contains 327253 sequences. (Running on oeis4.)