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!)
A019973 Decimal expansion of tangent of 75 degrees. 10
3, 7, 3, 2, 0, 5, 0, 8, 0, 7, 5, 6, 8, 8, 7, 7, 2, 9, 3, 5, 2, 7, 4, 4, 6, 3, 4, 1, 5, 0, 5, 8, 7, 2, 3, 6, 6, 9, 4, 2, 8, 0, 5, 2, 5, 3, 8, 1, 0, 3, 8, 0, 6, 2, 8, 0, 5, 5, 8, 0, 6, 9, 7, 9, 4, 5, 1, 9, 3, 3, 0, 1, 6, 9, 0, 8, 8, 0, 0, 0, 3, 7, 0, 8, 1, 1, 4, 6, 1, 8, 6, 7, 5, 7, 2, 4, 8, 5, 7 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

An equivalent definition of this sequence: decimal expansion of x > 1 satisfying x^2 - 4*x + 1 = 0. - Arkadiusz Wesolowski, Nov 28 2011

An algebraic integer of degree 2 with minimal polynomial x^2 - 4*x + 1. - Charles R Greathouse IV, Oct 17 2016

Length of the second longest diagonal in a regular 12-gon with unit side. - Mohammed Yaseen, Dec 13 2020

LINKS

G. C. Greubel, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Ivan Panchenko)

Wikipedia, Exact trigonometric constants

FORMULA

Equals 2 + sqrt(3) = cotangent of 15 degrees. - Rick L. Shepherd, Jul 04 2004

EXAMPLE

3.732050807568877293527446341505872366942805253810380628...

MATHEMATICA

RealDigits[Tan[75 Degree], 10, 120][[1]] (* Harvey P. Dale, Nov 08 2011 *)

RealDigits[2+Sqrt[3], 10, 100][[1]] (* G. C. Greubel, Nov 20 2018 *)

PROG

(PARI) sqrt(3)+2 \\ Charles R Greathouse IV, Oct 17 2016

(MAGMA) SetDefaultRealField(RealField(100)); 2 + Sqrt(3); // G. C. Greubel, Nov 20 2018

(Sage) numerical_approx(2+sqrt(3), digits=100) # G. C. Greubel, Nov 20 2018

CROSSREFS

Cf. A002194 (sqrt(3)).

Sequence in context: A296442 A021272 A135613 * A010623 A283245 A066065

Adjacent sequences:  A019970 A019971 A019972 * A019974 A019975 A019976

KEYWORD

nonn,cons

AUTHOR

N. J. A. Sloane

EXTENSIONS

Checked by Neven Juric (neven.juric(AT)apis-it.hr), Feb 04 2008

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 25 17:57 EDT 2021. Contains 347659 sequences. (Running on oeis4.)