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.

A351208 Decimal expansion of the 11th root of 3.

Original entry on oeis.org

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

Views

Author

Mark Andreas, Feb 04 2022

Keywords

Examples

			1.1050315033964...
		

Crossrefs

Cf. A246710 (8th root), A011446 (9th root), A246711 (10th root).

Programs

  • Maple
    Digits:=100: evalf(3^(1/11));
  • Mathematica
    RealDigits[3^(1/11), 10, 108][[1]]
  • PARI
    sqrtn(3, 11)
    
  • Python
    from sympy import integer_nthroot
    def A351208(n): return integer_nthroot(3*10**(11*(n-1)),11)[0] % 10 # Chai Wah Wu, Mar 07 2022

Formula

Equals 3^(1/11).

A351209 Decimal expansion of the 12th root of 3.

Original entry on oeis.org

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

Views

Author

Mark Andreas, Feb 07 2022

Keywords

Examples

			1.0958726911352443801600191280725486527997513...
		

Crossrefs

Cf. A246710 (8th root), A011446 (9th root), A246711, (10th root), A351208 (11th root).

Programs

  • Maple
    Digits:=100: evalf(3^(1/12));
  • Mathematica
    RealDigits[3^(1/12), 10, 108][[1]]
  • PARI
    sqrtn(3,12)
    
  • Python
    from sympy import integer_nthroot
    def A351209(n): return integer_nthroot(3*10**(12*(n-1)),12)[0] % 10 # Chai Wah Wu, Mar 07 2022

Formula

Equals 3^(1/12).

A010769 Decimal expansion of 7th root of 2.

Original entry on oeis.org

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

Views

Author

Keywords

Comments

This is also the unique positive attractor of the mapping M(x) = sqrt(sqrt(sqrt(2*x))). In general, (p^N-1)-th root of a number f can be approximated by iterating the mapping M(x) = (f*x)^(1/p^N). The convergence is very fast. In this case, p=2, N=3, and f=2. In the form "evaluate the 3rd (or 7th or 15th) root of a number using only square roots", the insight is usable as a recreational math puzzle. - Stanislav Sykora, Oct 26 2015

Examples

			1.104089513673812337649505387623...
		

Crossrefs

Cube roots (p=2,N=2) for various f: A002580 (2), A002581 (3), A005480 (4), A010582 (10), A092041 (e). 7th roots (p=2,N=3): A246709 (3), A011186 (4), A011201 (5), A011276 (10), A092516 (e). 8th roots (p=3,N=2): A010770 (2), A246710 (3), A011202 (5), A011277 (10). 15th roots (p=2,N=4): A010777(2), A011194(4), A011209(5), A011284(10). - Stanislav Sykora, Oct 26 2015

Programs

  • Mathematica
    RealDigits[N[2^(1/7), 100]][[1]] (* Vincenzo Librandi, Apr 02 2013 *)
    RealDigits[Surd[2,7],10,120][[1]] (* Harvey P. Dale, Sep 05 2022 *)
  • PARI
    sqrtn(2,7) \\ Charles R Greathouse IV, Apr 15 2014
    
  • PARI
    { default(realprecision, 100); x= 2^(1/7); for(n=1, 100, d=floor(x); x=(x-d)*10; print1(d, ", ")) } \\ Altug Alkan, Nov 14 2015

Formula

Equals Product_{k>=0} (1 + (-1)^k/(7*k + 6)). - Amiram Eldar, Jul 29 2020
Showing 1-3 of 3 results.