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!)
A178817 Decimal expansion of the area of the regular 7-gon (heptagon) of edge length 1. 10
3, 6, 3, 3, 9, 1, 2, 4, 4, 4, 0, 0, 1, 5, 8, 8, 9, 9, 2, 5, 3, 6, 1, 9, 3, 0, 0, 7, 6, 0, 0, 2, 2, 0, 5, 7, 8, 7, 3, 5, 0, 1, 0, 3, 6, 1, 5, 9, 5, 4, 4, 4, 9, 1, 7, 1, 4, 5, 9, 8, 0, 4, 0, 9, 5, 1, 0, 2, 9, 9, 8, 5, 2, 3, 6, 3, 0, 4, 6, 0, 0, 5, 5, 6, 2, 7, 3, 0, 7, 1, 5, 2, 9, 5, 8, 1, 0, 8, 9, 4, 3, 7, 1, 0, 4 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..10000

Wikipedia, Heptagon

Wikipedia, Regular polygon

FORMULA

Digits of (7/4) * cot(Pi/7).

EXAMPLE

3.63391244400158899253619300760022057873501036159544491714598040951029...

MAPLE

evalf[120]((7/4)*cot(Pi/7)); # Muniru A Asiru, Jan 22 2019

MATHEMATICA

RealDigits[7*Cot[Pi/7]/4, 10, 100][[1]]

PROG

(PARI) p=7; a=(p/4)*cotan(Pi/p)  \\ Set realprecision in excess. - Stanislav Sykora, Apr 12 2015

(MAGMA) SetDefaultRealField(RealField(100)); R:=RealField(); 7*Cot(Pi(R)/7)/4; // G. C. Greubel, Jan 22 2019

(Sage) numerical_approx(7*cot(pi/7)/4, digits=100) # G. C. Greubel, Jan 22 2019

CROSSREFS

Cf. A178818.

Cf. Areas of other regular polygons: A120011, A102771, A104956, A090488, A256853, A178816, A256854, A178809.

Sequence in context: A256158 A123060 A204931 * A275363 A155503 A010619

Adjacent sequences:  A178814 A178815 A178816 * A178818 A178819 A178820

KEYWORD

nonn,cons,easy

AUTHOR

Vladimir Joseph Stephan Orlovsky, Jun 16 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 February 23 21:20 EST 2020. Contains 332195 sequences. (Running on oeis4.)