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 1-4 of 4 results.

A084945 Decimal expansion of Golomb-Dickman constant.

Original entry on oeis.org

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

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Author

Eric W. Weisstein, Jun 13 2003

Keywords

Comments

The first 27 digits form a prime. - Jonathan Vos Post, Nov 12 2004
The first 1659 digits form a prime. - David Broadhurst, Apr 02 2010
The average number of digits in the largest prime factor of a random x-digit number is asymptotically x times this constant. - Charles R Greathouse IV, Jul 28 2015
Named after the American mathematician Solomon W. Golomb (1932 - 2016) and the Swedish actuary Karl Dickman (1861 - 1947). - Amiram Eldar, Aug 25 2020

Examples

			0.62432998854355087...
		

References

  • Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, pp. 284-287.

Crossrefs

Programs

  • Maple
    E1:= z-> int(exp(-t)/t, t=z..infinity):
    lambda:= int(exp(-x-E1(x)), x=0..infinity):
    s:= convert(evalf(lambda, 130), string):
    seq(parse(s[n+1]), n=1..120); # Alois P. Heinz, Nov 20 2011
  • Mathematica
    NIntegrate[Exp[LogIntegral[x]], {x, 0, 1}, WorkingPrecision->110, MaxRecursion->20]
  • PARI
    intnum(x=0,1-1e-9,exp(-eint1(-log(x)))) \\ Charles R Greathouse IV, Jul 28 2015
    
  • PARI
    default(realprecision, 103);
    limitnum(n->intnum(x=0, 1-1/n, exp(-eint1(-log(x))))) \\ Gheorghe Coserea, Sep 26 2018

Formula

From Amiram Eldar, Aug 25 2020: (Start)
Equals Integral_{x=0..1} exp(li(x)) dx, where li(x) is the logarithmic integral.
Equals Integral_{x=0..oo} exp(-x + Ei(-x)) dx, where Ei(x) is the exponential integral.
Equals Integral_{x=0..1} F(x/(1-x)) dx, where F(x) is the Dickman function. (End)

A225337 Incrementally largest terms in the continued fraction of the Golomb-Dickman constant.

Original entry on oeis.org

0, 1, 22, 28, 43, 48, 66, 491, 1706, 4763, 38371
Offset: 1

Views

Author

Eric W. Weisstein, Jul 25 2013

Keywords

Crossrefs

Cf. A225363 (positions of largest terms).
Cf. A225336 (continued fraction of the Golomb-Dickman constant).
Cf. A084945 (decimal expansion of the Golomb-Dickman constant).

A225363 Positions of incrementally largest terms in the continued fraction expansion of the Golomb-Dickman constant.

Original entry on oeis.org

0, 1, 6, 24, 39, 50, 52, 72, 259, 1002, 4610
Offset: 1

Views

Author

Eric W. Weisstein, Jul 25 2013

Keywords

Crossrefs

Cf. A225337 (incrementally largest terms).
Cf. A225336 (continued fraction of the Golomb-Dickman constant).
Cf. A084945 (decimal expansion of the Golomb-Dickman constant).

A225364 Position of first occurrence of n in the continued fraction for the Golomb-Dickman constant.

Original entry on oeis.org

1, 8, 9, 30, 25, 18, 110, 242, 59, 100, 12, 71, 28, 153, 225, 114, 159, 66, 75, 102, 924, 6, 631, 150, 299, 434, 701, 24, 1687, 196, 1482, 779, 1552, 2658, 505, 496, 255, 46, 1626, 183, 2551, 1083, 39, 665, 1419, 678, 1676, 50, 1027, 2047, 3726, 1309, 2327
Offset: 1

Views

Author

Eric W. Weisstein, Jul 25 2013

Keywords

Examples

			The c.f. for lambda is [0; 1, 1, 1, 1, 1, 22, 1, 2, 3, 1, ..], so
a(1) = 1 (1 occurs first at term a_1).
a(2) = 8 (2 occurs first at term a_8).
a(3) = 9 (3 occurs first at term a_9).
		

Crossrefs

Cf. A225336 (continued fraction of the Golomb-Dickman constant).
Cf. A084945 (decimal expansion of the Golomb-Dickman constant).
Showing 1-4 of 4 results.