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.

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A108587 a(n) = floor(n/(1-sin(1))).

Original entry on oeis.org

6, 12, 18, 25, 31, 37, 44, 50, 56, 63, 69, 75, 82, 88, 94, 100, 107, 113, 119, 126, 132, 138, 145, 151, 157, 164, 170, 176, 182, 189, 195, 201, 208, 214, 220, 227, 233, 239, 246, 252, 258, 264, 271, 277, 283, 290, 296, 302, 309, 315, 321, 328, 334, 340, 346
Offset: 1

Views

Author

Reinhard Zumkeller, Jun 11 2005

Keywords

Comments

Beatty sequence for 1/(1-sin(1)); complement of A108120.

Crossrefs

Programs

  • Magma
    [Floor(n/(1-Sin(1))): n in [1..60]]; // G. C. Greubel, Dec 19 2022
    
  • Mathematica
    Table[Floor[n/(1-Sin[1])], {n, 60}] (* G. C. Greubel, Dec 19 2022 *)
  • SageMath
    [int(n/(1-sin(1))) for n in range(1,61)] # G. C. Greubel, Dec 19 2022

A206530 Decimal expansion of 1/(1-sin(1)).

Original entry on oeis.org

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

Views

Author

Seiichi Kirikami, Feb 11 2012

Keywords

Comments

The value of the limit of (A206307+6*A206308) / (A206308).

Examples

			6.3079935164437400275135217398...
		

References

  • E. W. Cheney, Introduction to Approximation Theory, McGraw-Hill, Inc., 1966.

Crossrefs

Programs

  • Magma
    SetDefaultRealField(RealField(150)); 1/(1-Sin(1)); // G. C. Greubel, Dec 20 2022
    
  • Mathematica
    RealDigits[N[1/(1-Sin[1]), 150]][[1]]
  • SageMath
    numerical_approx(1/(1-sin(1)), digits=150) # G. C. Greubel, Dec 20 2022

Formula

Equals 1/(1-A049469).
A206307/A206308 + 6 -> 1/(1-A049469).
Abs(A206308/(1-sin(1)) - (A206307 + 6*A206308)) -> 0.

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.

A067919 Engel expansion of sin(1).

Original entry on oeis.org

2, 2, 3, 11, 14, 27, 28, 66, 212, 231, 552, 2842, 3774, 6038, 6784, 10950, 32948, 78591, 97875, 98342, 123569, 139837, 159698, 1102838, 3256476, 20329622, 34385124, 60999878, 82669919, 85820365, 389915995, 4274338879, 18907353107, 62875944378, 74931184173
Offset: 1

Views

Author

Benoit Cloitre, Mar 03 2002

Keywords

Examples

			sin(1) = 0.84147... = A049469 has the Engel expansion 1/2 + 1/(2*2) + 1/(2*2*3) + ...
		

Crossrefs

See A006784 for explanation of Engel expansions.

Programs

  • Mathematica
    EngelExp[A_,n_]:=Join[Array[1&,Floor[A]],First@Transpose@NestList[{Ceiling[1/Expand[ #[[1]]#[[2]]-1]],Expand[ #[[1]]#[[2]]-1]}&,{Ceiling[1/(A-Floor[A])],A-Floor[A]},n-1]]; EngelExp[N[Sin[1],6! ],50] (* Vladimir Joseph Stephan Orlovsky, Jun 13 2009 *)
  • PARI
    s=sin(1); for(i=1,30,s=s*ceil(1/s)-1; print1(ceil(1/s),","); );

Extensions

a(1) inserted by Hauke Worpel (hw1(AT)email.com), Jun 01 2003
Edited by N. J. A. Sloane, Nov 01 2008 at the suggestion of R. J. Mathar

A233383 Decimal expansion of the absolute value of Sum_{n>=1} (-1)^n*sin(1/n).

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Dec 08 2013

Keywords

Comments

If the contribution of the first term, -sin(1) = -A049469, is omitted, the constant becomes Sum_{n>=1} (sin(1/(2n)) - sin(1/(2n+1))) = 0.29067413667396703114243536419518058522...

Examples

			0.550796848133929475510066957...
		

Programs

  • Maple
    M := 141 :
    Digits := 120 :
    s := sin(1/2/n)-sin(1/(2*n+1)) :
    add(subs(n=i,s),i=1..M) :
    pre := evalf(%) :
    zetaM := proc(s,M)
        local n ;
        Zeta(s)-add(1/n^s,n=1..M) ;
        evalf(%) ;
    end proc:
    for dd from 75 to 90 by 5 do
        subs(n=1/eps,s) ;
        taylor(%,eps=0,dd+1) ;
        t := gfun[seriestolist](%,'ogf') ;
        add( op(j,t)*zetaM(j-1,M),j=3..nops(t)) ;
        x := pre+% ;
        print(x) ;
    end do:
    # now sum_{n>=1} (-1)^n*sin(1/n) = -0.5570986.
    x-sin(1.0) ;
  • Mathematica
    digits = 105; NSum[(-1)^n*Sin[1/n], {n, 1, Infinity}, Method -> "AlternatingSigns", WorkingPrecision -> digits+10] // RealDigits[#, 10, digits]& // First (* Jean-François Alcover, Feb 24 2014 *)

A280188 Base-60 (Babylonian or sexagesimal) expansion of sine of 1 degree.

Original entry on oeis.org

1, 2, 49, 43, 11, 14, 44, 16, 26, 18, 28, 49, 20, 26, 50, 41, 13, 6, 46, 25, 26, 26, 34, 6, 40, 18, 50, 31, 6, 35, 20, 44, 6, 39, 18, 5, 38, 58, 2, 0, 5, 4, 33, 59, 11, 35, 33, 50, 34, 7, 56, 43, 38, 30, 15, 49, 36, 42, 6, 43, 10, 38, 45, 53, 15, 59, 7, 19, 46
Offset: 1

Views

Author

Mohammad K. Azarian, Dec 28 2016

Keywords

Comments

The Fifteenth Century Persian mathematician Jamshid Al-Kashi was the first to calculate the value of sine of one degree correct to ten sexagesimal places (17 decimal digits) in his Risala al-Watar wa'l Jaib.

Crossrefs

Programs

  • Mathematica
    RealDigits[Sin[1 Degree], 60, 200][[1]]

Extensions

More terms from Jon E. Schoenfield, Jan 13 2017

A372339 Decimal expansion of Sum_{k>=0} (-1)^k * (k+2) / ((k+1)*(2*k)!).

Original entry on oeis.org

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

Views

Author

Clark Kimberling, Apr 28 2024

Keywords

Examples

			1.3038488872202121655078144655895278104420573...
		

Crossrefs

Programs

  • Mathematica
    s = Sum[(-1)^k (k + 2)/((k + 1) (2 k)!), {k, 0, Infinity}]
    d = N[s, 100]
    First[RealDigits[d]]

Formula

Equals -2 + 3*cos(1) + 2*sin(1).

A091033 Third column (k=4) of array A090438 ((4,2)-Stirling2).

Original entry on oeis.org

1, 180, 25200, 4233600, 898128000, 239740300800, 79332244992000, 32011868528640000, 15509750302126080000, 8898339094906060800000, 5971815866682429603840000, 4637851802955964809216000000
Offset: 2

Views

Author

Wolfdieter Lang, Jan 23 2004

Keywords

Crossrefs

Cf. A091032 (second column of A090438 divided by 8), A091034 (fourth column divided by 24), A000384, A090438.

Programs

  • Mathematica
    a[n_] := (n-1)*(2*n-3)*(2*n)!/4!; Array[a, 12, 2] (* Amiram Eldar, Nov 03 2022 *)
  • PARI
    a(n) = (n-1)*(2*n-3)*(2*n)!/4!; \\ Amiram Eldar, Nov 03 2022

Formula

a(n) = A090438(n, 4), n>=2.
a(n) = (n-1)*(2*n-3)*(2*n)!/4! = binomial(2*(n-1), 2)*(2*n)!/4! = A000384(n-1)*(2*n)!/4!, n>=2.
E.g.f.: (6*hypergeom([1/2, 1], [], 4*x) - 4*hypergeom([1, 3/2], [], 4*x) + hypergeom([3/2, 2], [], 4*x) -3)/4! (cf. A090438).
From Amiram Eldar, Nov 03 2022: (Start)
Sum_{n>=2} 1/a(n) = -20 + 24*Gamma - 16*CoshIntegral(1) + 16*sinh(1) + 8*SinhIntegral(1).
Sum_{n>=2} (-1)^n/a(n) = 4 - 24*gamma + 16*cos(1) + 24*CosIntegral(1) - 16*sin(1) + 8*SinIntegral(1). (End)

A091034 Fourth column (k=5) of array A090438 ((4,2)-Stirling2) divided by 24.

Original entry on oeis.org

1, 280, 70560, 19958400, 6659452800, 2644408166400, 1244905998336000, 689322235650048000, 444916954745303040000, 331767548149023866880000, 283424276847308960563200000, 275246422218908346286080000000
Offset: 3

Views

Author

Wolfdieter Lang, Jan 23 2004

Keywords

Crossrefs

Cf. A091033 (third column of A090438), A091035 (fifth column), A090438.

Programs

  • Mathematica
    a[n_] := (n - 1)*(n - 2)*(2*n - 3)*(2*n)!/(5!*(3!)^2); Array[a, 12, 3] (* Amiram Eldar, Nov 03 2022 *)
  • PARI
    a(n) = (n-1)*(n-2)*(2*n-3)*(2*n)!/(5!*(3!)^2); \\ Amiram Eldar, Nov 03 2022

Formula

a(n) = A090438(n, 5)/24, n>=3.
a(n) = (n-1)*(n-2)*(2*n-3)*(2*n)!/(5!*(3!)^2), n>=3.
E.g.f.: (Sum_{p=2..5} (((-1)^(p+1))*binomial(5, p)*hypergeom([(p-1)/2, p/2], [], 4*x)) + 4)/(5!*4!) (cf. A090438).
From Amiram Eldar, Nov 03 2022: (Start)
Sum_{n>=3} 1/a(n) = 2010 - 4680*Gamma + 1800*cosh(1) + 4680*CoshIntegral(1) - 2520*sinh(1) - 2880*SinhIntegral(1).
Sum_{n>=3} (-1)^(n+1)/a(n) = -2010 - 3960*gamma + 3240*cos(1) + 3960*CosIntegral(1) - 1800*sin(1) + 2880*SinIntegral(1). (End)
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