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 1-8 of 8 results.

A072334 Decimal expansion of e^2.

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Jul 15 2002

Keywords

Comments

Also where x^(1/sqrt(x)) is a maximum. - Robert G. Wilson v, Oct 22 2014

Examples

			7.389056098930650...
		

References

  • Ovidiu Furdui, Limits, Series, and Fractional Part Integrals: Problems in Mathematical Analysis, New York: Springer, 2013. See Problem 1.4, pages 2 and 28-29.

Crossrefs

Cf. A001204 (continued fraction).

Programs

  • Magma
    SetDefaultRealField(RealField(100)); Exp(1)^2; // Vincenzo Librandi, Apr 05 2020
  • Mathematica
    RealDigits[E^2, 10, 100][[1]] (* Vincenzo Librandi, Apr 05 2020 *)
  • PARI
    default(realprecision, 20080); x=exp(2); for (n=1, 20000, d=floor(x); x=(x-d)*10; write("b072334.txt", n, " ", d)); \\ Harry J. Smith, Apr 30 2009
    

Formula

Equals Sum_{n>=0} Sum_{k>=0} 1/(n!*k!). - Fredrik Johansson, Apr 21 2006
Equals Sum_{n>=0} 2^n/n!. - Daniel Hoyt Nov 20 2020
From Peter Bala, Jan 13 2022: (Start)
e^2 = Sum_{n >= 0} 2^n/n!. Faster converging series include
e^2 = 8*Sum_{n >= 0} 2^n/(p(n-1)*p(n)*n!), where p(n) = n^2 - n + 2 and
e^2 = -48*Sum_{n >= 0} 2^n/(q(n-1)*q(n)*n!), where q(n) = n^3 + 5*n - 2.
e^2 = 7 + Sum_{n >= 0} 2^(n+3)/((n+2)^2*(n+3)^2*n!) and
7/e^2 = 1 - Sum_{n >= 0} (-2)^(n+1)*n^2/(n+2)!.
e^2 = 7 + 2/(5 + 1/(7 + 1/(9 + 1/(11 + ...)))) (follows from the fact that A004273 is the continued fraction expansion of tanh(1) = (e^2 - 1)/ (e^2 + 1)). Cf. A001204. (End)
Equals lim_{n->oo} (Sum_{k=1..n} 1/binomial(n,k)^x)^(n^x), for all real x > 1/2 (Furdui, 2013). - Amiram Eldar, Mar 26 2022

A091933 Decimal expansion of e^3.

Original entry on oeis.org

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

Views

Author

Mohammad K. Azarian, Mar 16 2004

Keywords

Comments

Also where x^(1/x^(1/3)) is a maximum. - Robert G. Wilson v, Oct 22 2014

Examples

			exp(3) = e^3 = 20.0855369231876677409285296545817178969879... - _Harry J. Smith_, Apr 30 2009
		

Crossrefs

Programs

  • Maple
    Digits:=100: evalf(exp(3)); # Wesley Ivan Hurt, Jul 07 2014
  • Mathematica
    RealDigits[E^3, 10, 100][[1]] (* Alonso del Arte, Jul 07 2014 *)
  • PARI
    default(realprecision, 20080); x=exp(3)/10; for (n=2, 20000, d=floor(x); x=(x-d)*10; write("b091933.txt", n, " ", d)); \\ Harry J. Smith, Apr 30 2009

Formula

From Peter Bala, Jan 12 2022: (Start)
e^3 = Sum_{n >= 0} 3^n/n!. Faster converging series include
e^3 = 18*Sum_{n >= 0} 3^n/(p(n-1)*p(n)*n!), where p(n) = n^2 - 3*n + 5 and
e^3 = -162*Sum_{n >= 0} 3^n/(q(n-2)*q(n-1)*n!), where q(n) = n^3 + 8*n - 3.
e^3 = 22 - Sum_{n >= 0} 3^(n+4)/((n+3)^2*(n+4)^2*n!) and
22/e^3 = 1 - 2*Sum_{n >= 0} (-3)^(n+2)*n^2/(n+3)!.
e^3 = lim_{n -> oo} f(n+2)*f(n)/(n^2*f(n+1)^2), where f(n) = n^(n^2). Compare with e = lim_{n -> oo} g(n+1)/(n*g(n)), where g(n) = n^n. (End)

A092426 Decimal expansion of e^4.

Original entry on oeis.org

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

Views

Author

Mohammad K. Azarian, Mar 22 2004

Keywords

Examples

			54.598150033144239078110261202860878402790737038614....
		

Crossrefs

Cf. A058283 (continued fraction).

Programs

  • Maple
    Digits:=100: evalf(exp(4)); # Wesley Ivan Hurt, Sep 01 2014
  • Mathematica
    RealDigits[E^4, 10, 100][[1]] (* Alonso del Arte, Aug 31 2014 *)
  • PARI
    default(realprecision, 20080); x=exp(1)^4/10; for (n=2, 20000, d=floor(x); x=(x-d)*10; write("b092426.txt", n, " ", d)); \\ Harry J. Smith, Jun 22 2009

Formula

From Peter Bala, Jan 12 2022: (Start)
e^4 = 45 + 2*Sum_{n >= 0} 4^(n+4)/((n+4)^2*(n+5)^2*n!).
45/e^4 = 1 - 3*Sum_{n >= 0} (-4)^(n+3)*n^2/(n+4)!. (End)
Largest solution to sqrt(log(x)) = log(sqrt(x)), the other solution being x = 1. - Andrea Pinos, Jan 23 2024

A092511 Decimal expansion of e^5.

Original entry on oeis.org

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

Views

Author

Mohammad K. Azarian, Apr 05 2004

Keywords

Examples

			148.413159102
		

Crossrefs

Programs

Formula

From Peter Bala, Jan 12 2022: (Start)
e^5 = 456 - Sum_{n >= 0} 5^(n+6)/((n+5)^2*(n+6)^2*n!).
456/e^5 = 1 - 4!*Sum_{n >=0} (-5)^(n+4)*n^2/(n+5)!. (End)

A092513 Decimal expansion of e^7.

Original entry on oeis.org

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

Views

Author

Mohammad K. Azarian, Apr 05 2004

Keywords

Examples

			1096.6331584284585992...
		

Crossrefs

Programs

Formula

From Peter Bala, Jan 12 2022: (Start)
e^7 = (1/167)*Sum_{n >= 0} 7^(n+8)/((n+7)^2*(n+8)^2*n!) - 19440/167.
19440/e^7 = 7!*Sum_{n >= 0} (-7)^(n+5)*n^2/(n+7)! - 167. (End)

A254528 Number of decimal digits in the integer part of e^n.

Original entry on oeis.org

1, 1, 1, 2, 2, 3, 3, 4, 4, 4, 5, 5, 6, 6, 7, 7, 7, 8, 8, 9, 9, 10, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 14, 15, 15, 16, 16, 17, 17, 17, 18, 18, 19, 19, 20, 20, 20, 21, 21, 22, 22, 23, 23, 24, 24, 24, 25, 25, 26, 26, 27, 27, 27, 28, 28, 29, 29, 30, 30, 30, 31, 31, 32, 32, 33, 33
Offset: 0

Views

Author

Robert G. Wilson v, Feb 01 2015

Keywords

Examples

			e^10 = 22026.46579480671..., so a(10) = 5.
		

Crossrefs

Cf. A001113, A072334, A091933, A092426, A092511, A092512, A092513 (see their offsets).

Programs

  • Mathematica
    f[n_] := 1 + Floor@ Log10@ Exp@ n; Array[f, 75, 0]
    Table[Sum[DigitCount[Floor[Exp[1]^k]][[n]], {n, 1, 10}], {k, 0, 150}] (* Benedict W. J. Irwin, Apr 13 2016 *)
    IntegerLength[Floor[E^Range[0,80]]] (* Harvey P. Dale, Aug 28 2017 *)
  • PARI
    a(n) = localprec(n+1); #Str(floor(exp(n))); \\ Michel Marcus, Dec 05 2020

Formula

a(n) = A055642(A000149(n)). - Amiram Eldar, May 25 2024

A277117 Decimal expansion of e^6/(Pi^5+Pi^4), where e = exp(1).

Original entry on oeis.org

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

Views

Author

Keywords

Examples

			1.0000000438081076299476374320122890058190409215306036959233520...
		

References

  • D. Wilson, pers. comm.

Crossrefs

Programs

  • Mathematica
    RealDigits[E^6/(Pi^5+Pi^4),10,120][[1]] (* Harvey P. Dale, Apr 07 2019 *)
  • PARI
    exp(6)/(Pi^5+Pi^4) \\ Michel Marcus, Oct 02 2016

Formula

Equals A092512 /(A092731 + A092425).

A376994 Decimal expansion of Pi^4 + Pi^5.

Original entry on oeis.org

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

Views

Author

Stefano Spezia, Oct 12 2024

Keywords

Comments

This constant is very close to e^6 = A092512.

Examples

			403.4287758192838904991816427321407177300282923...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[Pi^4+Pi^5,10,100][[1]]
Showing 1-8 of 8 results.