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.

A019940 Decimal expansion of tangent of 42 degrees.

Original entry on oeis.org

9, 0, 0, 4, 0, 4, 0, 4, 4, 2, 9, 7, 8, 3, 9, 9, 4, 5, 1, 2, 0, 4, 7, 7, 2, 0, 3, 8, 8, 5, 3, 7, 1, 7, 0, 2, 0, 7, 6, 4, 6, 6, 2, 1, 1, 2, 9, 9, 4, 8, 5, 2, 8, 2, 4, 2, 7, 0, 7, 9, 0, 8, 3, 9, 2, 2, 4, 0, 1, 7, 1, 4, 2, 5, 2, 5, 0, 2, 5, 3, 1, 8, 6, 2, 6, 3, 1, 1, 5, 9, 8, 6, 6, 3, 3, 8, 2, 8, 3
Offset: 0

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Comments

Also the decimal expansion of cotangent of 48 degrees. - Ivan Panchenko, Sep 01 2014

Examples

			0.900404044297839945120477203885371702076466211299485282427079...
		

Crossrefs

Cf. A019851 (sine of 42 degrees)

Programs

  • Magma
    SetDefaultRealField(RealField(100)); R:= RealField(); Tan(7*Pi(R)/30); // G. C. Greubel, Nov 25 2018
    
  • Mathematica
    RealDigits[Tan[42 Degree],10,120][[1]] (* Harvey P. Dale, Sep 05 2012 *)
    RealDigits[Tan[7*Pi/30], 10, 100][[1]] (* G. C. Greubel, Nov 25 2018 *)
  • PARI
    default(realprecision, 100); tan(7*Pi/30) \\ G. C. Greubel, Nov 25 2018
    
  • Sage
    numerical_approx(tan(7*pi/30), digits=100) # G. C. Greubel, Nov 25 2018

Formula

Equals sqrt(7 + 2*sqrt(5) - 2*sqrt(3*(5 + 2*sqrt(5)))). - G. C. Greubel, Nov 25 2018