cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-3 of 3 results.

A069976 Interior angle of a regular polygon of n sides, rounded to nearest integer.

Original entry on oeis.org

60, 90, 108, 120, 129, 135, 140, 144, 147, 150, 152, 154, 156, 158, 159, 160, 161, 162, 163, 164, 164, 165, 166, 166, 167, 167, 168, 168, 168, 169, 169, 169, 170, 170, 170, 171, 171, 171, 171, 171, 172, 172, 172, 172, 172, 173, 173, 173, 173, 173, 173, 173, 173, 174
Offset: 3

Views

Author

Kristie Smith (kristie10spud(AT)hotmail.com), Apr 30 2002

Keywords

Examples

			a(5) = (3*180)/5 = 108.
a(720) = 180; the maximum value. - _Robert G. Wilson v_, Mar 16 2016

References

  • Alexander Koeberlein, Elementary Geometry for College Students, 2nd Edition, Houghton Mifflin Company, Boston, 1999

Crossrefs

Cf. A100659.

Programs

  • Mathematica
    f[n_] := Round[180 (n - 2)/n]; Array[f, 55, 3] (* Robert G. Wilson v, Mar 16 2016 *)
  • PARI
    a(n) = round((n-2)*180/n); \\ Michel Marcus, Aug 27 2013

Formula

a(n) = round(((n-2)*180)/n).

Extensions

More terms from Michel Marcus, Aug 27 2013

A110546 In degrees, values of interior angles of regular polygons whose angles are integers.

Original entry on oeis.org

60, 90, 108, 120, 135, 140, 144, 150, 156, 160, 162, 165, 168, 170, 171, 172, 174, 175, 176, 177, 178, 179
Offset: 1

Views

Author

Alexandre Wajnberg, Sep 11 2005

Keywords

Comments

The number of sides for which the interior angles in degrees are integers is given by A018412 (except the first two terms).
Integers of the form (k-2)*180/k where k >= 3. - Jason Yuen, Sep 05 2024

Examples

			a(3)=108, i.e., the value (in degrees) of the interior angles of the third polygon whose angles are integers (the pentagon).

Crossrefs

Cf. A069976, A100659, A018412.

Formula

a(n) = (A018412(n+2)-2)*180/A018412(n+2). - Jason Yuen, Sep 05 2024

A110547 Number of sides of regular polygons whose interior angles (in degrees) are not integers.

Original entry on oeis.org

7, 11, 13, 14, 16, 17, 19, 21, 22, 23, 25, 26, 27, 28, 29, 31, 32, 33, 34, 35, 37, 38, 39, 41, 42, 43, 44, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86
Offset: 1

Views

Author

Alexandre Wajnberg, Sep 11 2005

Keywords

Comments

Numbers that are not divisors of 360.

Examples

			a(3)=13 because the third polygon whose interior angle in degrees is not an integer is the 13-gon.

Crossrefs

Cf. A069976, A100659, A018412.

Programs

  • Mathematica
    Select[Range[86],!Divisible[360,#] &] (* Stefano Spezia, Sep 05 2024 *)
Showing 1-3 of 3 results.

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