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.

Previous Showing 11-15 of 15 results.

A346927 Decimal expansion of the Dirichlet eta function at 10.

Original entry on oeis.org

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

Views

Author

Sean A. Irvine, Aug 07 2021

Keywords

Examples

			0.999039507598271565639221845699341831425929649666890...
		

References

  • L. B. W. Jolley, Summation of Series, Dover, 1961, Eq. (306).

Crossrefs

Programs

  • Mathematica
    RealDigits[DirichletEta[10], 10, 100][[1]] (* Amiram Eldar, Aug 08 2021 *)
  • PARI
    -polylog(10, -1) \\ Michel Marcus, Aug 08 2021

Formula

Equals 73 * Pi^10 / (2^9 * 3^5 * 5 * 11).
Equals (511/512) * zeta(10).
Equals Sum_{k>=1} (-1)^(k+1) / k^10.
Equals eta(10).

A136038 a(n) = n^6 - n^4.

Original entry on oeis.org

0, 0, 48, 648, 3840, 15000, 45360, 115248, 258048, 524880, 990000, 1756920, 2965248, 4798248, 7491120, 11340000, 16711680, 24054048, 33907248, 46915560, 63840000, 85571640, 113145648, 147756048, 190771200, 243750000, 308458800, 386889048, 481275648
Offset: 0

Views

Author

Rolf Pleisch, Mar 16 2008

Keywords

Crossrefs

Programs

Formula

From R. J. Mathar, Feb 06 2010: (Start)
a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7).
G.f.: 24*x^2*(1+x)*(2*x^2+11*x+2)/(1-x)^7. (End)
From Amiram Eldar, Jan 12 2021: (Start)
Sum_{n>=2} 1/a(n) = 11/4 - Pi^2/6 - Pi^4/90 = 11/4 - A013661 - A013662.
Sum_{n>=2} (-1)^n/a(n) = 7*Pi^4/720 + Pi^2/12 - 7/4 = A267315 + A072691 - 7/4. (End)

A349252 Decimal expansion of Sum_{k>=1} (-1)^k * log(k) / k^4.

Original entry on oeis.org

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

Views

Author

Ilya Gutkovskiy, Nov 12 2021

Keywords

Comments

First derivative of the Dirichlet eta function at 4.

Examples

			0.0334788045785650663859568547887377997137597304057...
		

Crossrefs

Programs

  • Mathematica
    Flatten[{0, RealDigits[(Pi^4 Log[2] + 630 Zeta'[4])/720, 10, 120][[1]]}]
  • PARI
    sumalt(k=1, (-1)^k * log(k) / k^4) \\ Michel Marcus, Nov 12 2021

Formula

Equals (Pi^4 * log(2) + 630 * zeta'(4)) / 720.

A246967 Decimal expansion of the real positive solution to eta(x) = x.

Original entry on oeis.org

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

Views

Author

Michal Paulovic, Sep 08 2014

Keywords

Comments

Fixed point of Dirichlet eta function.

Examples

			0.6293340940...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[x /. FindRoot[DirichletEta[x] - x, {x, 0}, WorkingPrecision -> 120], 10, 100] [[1]] (* Amiram Eldar, May 24 2021 *)
  • PARI
    solve(n=0,2,(1-2^(1-n))*zeta(n)-n) \\ Edward Jiang, Sep 08 2014

A269481 Continued fraction expansion of the Dirichlet eta function at 4.

Original entry on oeis.org

0, 1, 17, 1, 7, 3, 3, 1, 7, 3, 6, 1, 1, 7, 1, 11, 1, 11, 5, 1, 2, 2, 2, 7, 1, 14, 6, 5, 1, 1, 1, 1, 10, 9, 1, 1, 5, 2, 2, 3, 2, 5, 2, 4, 1, 46, 312, 3, 3, 1, 15, 1, 2, 5, 2, 1, 1, 27, 1, 2, 1, 2, 11, 5, 2, 1, 482, 3, 2, 4, 2, 2, 3, 1, 3, 1, 2, 1, 1, 13, 1, 13, 1, 1, 67, 149, 7, 2, 2, 18, 1, 2, 1, 1, 1, 51, 1, 7, 1, 8
Offset: 0

Views

Author

Ilya Gutkovskiy, Feb 27 2016

Keywords

Comments

Continued fraction of Sum_{k>=1} (-1)^(k - 1)/k^4 = (7*Pi^4)/720 = 0.9470328294972459175765...

Examples

			1/1^4 - 1/2^4 + 1/3^4 - 1/4^4 + 1/5^4 - 1/6^4 +... = 1/(1 + 1/(17 + 1/(1 + 1/(7 + 1/(3 + 1/(3 + 1/...)))))).
		

Crossrefs

Programs

  • Mathematica
    ContinuedFraction[(7 Pi^4)/720, 100]
Previous Showing 11-15 of 15 results.