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 1-2 of 2 results.

A016634 Decimal expansion of log(11).

Original entry on oeis.org

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

Views

Author

Keywords

Examples

			2.3978952727983705440619435779651292998217068539374171752185677...
		

References

  • Milton Abramowitz and Irene A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 2.

Crossrefs

Cf. A016739 Continued fraction.

Programs

  • Mathematica
    RealDigits[Log[11], 10, 120][[1]] (* Harvey P. Dale, Mar 09 2014 *)
  • PARI
    default(realprecision, 20080); x=log(11); for (n=1, 20000, d=floor(x); x=(x-d)*10; write("b016634.txt", n, " ", d)); \\ Harry J. Smith, May 16 2009

Formula

log(11) = 2*Sum_{n >= 1} 1/(n*P(n, 6/5)*P(n-1, 6/5)), where P(n, x) denotes the n-th Legendre polynomial. The first 20 terms of the series gives the approximation log(11) = 2.3978952727(47...), correct to 10 decimal places. - Peter Bala, Mar 19 2024
Equals 2*(log 2+log 5 -log 3)+Sum_{k>=1} (-1)^k/(k*100^k). - R. J. Mathar, Jun 10 2024

A068461 Factorial, or factoradic, expansion of log(11) = Sum_{n>=1} a(n)/n!, with a(n) as large as possible.

Original entry on oeis.org

2, 0, 2, 1, 2, 4, 3, 3, 1, 2, 4, 0, 3, 13, 1, 12, 12, 13, 1, 16, 16, 0, 16, 12, 10, 9, 1, 23, 3, 22, 0, 28, 11, 14, 23, 16, 0, 14, 6, 1, 1, 14, 4, 25, 43, 0, 29, 10, 41, 19, 47, 14, 0, 51, 10, 47, 37, 45, 46, 56, 57, 45, 10, 32, 61, 15, 9, 67, 5, 9, 22, 25, 65, 56, 24, 12, 71, 9, 57
Offset: 1

Views

Author

Benoit Cloitre, Mar 10 2002

Keywords

Examples

			log(11) = 2 + 0/2! + 2/3! + 1/4! + 2/5! + 4/6! + 3/7! + 3/8! + 1/9! + ...
		

Crossrefs

Cf. A016634 (decimal expansion), A016739 (continued fraction).
Cf. A007514 vs. A075874 for factoradic expansion.
Cf. A067882 (log(2)), A322334 (log(3)), A322333 (log(5)), A068460 (log(7)).

Programs

  • Magma
    SetDefaultRealField(RealField(250));  [Log(11)] cat [Floor(Factorial(n)*Log(11)) - n*Floor(Factorial((n-1))*Log(11)) : n in [2..80]]; // G. C. Greubel, Dec 05 2018
    
  • Mathematica
    With[{b = Log[11]}, Table[If[n == 1, Floor[b], Floor[n!*b] - n*Floor[(n - 1)!*b]], {n, 1, 100}]] (* G. C. Greubel, Dec 05 2018 *)
  • PARI
    vector(30, n, if(n>1, t=t%1*n, t=log(11))\1) \\ Increase realprecision (e.g., \p500) to compute more terms. - M. F. Hasler, Nov 25 2018
    
  • PARI
    default(realprecision, 250); b = log(11); for(n=1, 80, print1(if(n==1, floor(b), floor(n!*b) - n*floor((n-1)!*b)), ", ")) \\ G. C. Greubel, Dec 05 2018
    
  • Sage
    def a(n):
        if n==1: return floor(log(11))
        else: return expand(floor(factorial(n)*log(11)) - n*floor(factorial(n-1)*log(11)))
    [a(n) for n in (1..80)] # G. C. Greubel, Dec 05 2018

Extensions

Name edited and keyword cons,easy removed by M. F. Hasler, Nov 26 2018
Showing 1-2 of 2 results.