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.

A337729 a(n) = (4*n+2)! * Sum_{k=0..n} 1 / (4*k+2)!.

Original entry on oeis.org

1, 361, 1819441, 43710250585, 3210080802962401, 563561785768079119561, 202205968733586788098486801, 132994909755454702268136738753721, 148026526435655214537290625514621562305, 262237873172349351865682580536682974917045801, 704454843460345510903820429747302209179158476142321
Offset: 0

Views

Author

Ilya Gutkovskiy, Sep 17 2020

Keywords

Crossrefs

Programs

  • Mathematica
    Table[(4 n + 2)! Sum[1/(4 k + 2)!, {k, 0, n}], {n, 0, 10}]
    Table[(4 n + 2)! SeriesCoefficient[(1/2) (Cosh[x] - Cos[x])/(1 - x^4), {x, 0, 4 n + 2}], {n, 0, 10}]
    Table[Floor[(1/2) (Cosh[1] - Cos[1]) (4 n + 2)!], {n, 0, 10}]
  • PARI
    a(n) = (4*n+2)!*sum(k=0, n, 1/(4*k+2)!); \\ Michel Marcus, Sep 17 2020

Formula

E.g.f.: (1/2) * (cosh(x) - cos(x)) / (1 - x^4) = x^2/2! + 361*x^6/6! + 1819441*x^10/10! + 43710250585*x^14/14! + ...
a(n) = floor(c * (4*n+2)!), where c = (cosh(1) - cos(1)) / 2 = A334364.

A334363 Decimal expansion of Sum_{k>=0} 1/(4*k+1)!.

Original entry on oeis.org

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

Views

Author

Ilya Gutkovskiy, Apr 24 2020

Keywords

Examples

			1/1! + 1/5! + 1/9! + ... = 1.008336089225848981767442...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[(Sin[1] + Sinh[1])/2, 10, 110] [[1]]
  • PARI
    suminf(k=0, 1/(4*k+1)!) \\ Michel Marcus, Apr 25 2020

Formula

Equals (sin(1) + sinh(1))/2.

A334365 Decimal expansion of Sum_{k>=0} 1/(4*k+3)!.

Original entry on oeis.org

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

Views

Author

Ilya Gutkovskiy, Apr 24 2020

Keywords

Examples

			1/3! + 1/7! + 1/11! + ... = 0.1668651044179524751...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[(Sinh[1] - Sin[1])/2, 10, 111] [[1]]
  • PARI
    suminf(k=0, 1/(4*k+3)!) \\ Michel Marcus, Apr 25 2020

Formula

Equals (sinh(1) - sin(1))/2.

A349804 Decimal expansion of cosh(1) - cos(1).

Original entry on oeis.org

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

Views

Author

Christoph B. Kassir, Dec 11 2021

Keywords

Examples

			1.00277832894710406107696901331408507...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[Cosh[1] - Cos[1], 10, 100][[1]] (* Amiram Eldar, Dec 11 2021 *)
  • PARI
    cosh(1) - cos(1)

Formula

Equals 2 * Sum_{k>=0} 1/(4*k+2)! = 2 * A334364. - Amiram Eldar, Dec 11 2021
Showing 1-4 of 4 results.