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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A091035 Fifth column (k=6) of array A090438 ((4,2)-Stirling2).

Original entry on oeis.org

1, 840, 352800, 139708800, 59935075200, 29088489830400, 16183777978368000, 10339833534750720000, 7563588230670151680000, 6303583414831453470720000, 5951909813793488171827200000, 6330667711034891964579840000000
Offset: 3

Views

Author

Wolfdieter Lang, Jan 23 2004

Keywords

Crossrefs

Cf. A091034 (fourth column of A090438 divided by 24), A091036 (sixth column divided by 48), A053134, A090438.

Programs

  • Mathematica
    Table[Binomial[2n-2,4] (2n)!/6!,{n,3,20}] (* Harvey P. Dale, Jun 07 2021 *)
  • PARI
    a(n) = binomial(2*n-2, 4)*(2*n)!/6!; \\ Amiram Eldar, Nov 03 2022

Formula

a(n) = A090438(n, 6), n>=3.
a(n) = binomial(2*n-2, 4)*(2*n)!/6! = A053134(n-3)*(2*n)!/6!, n>=3.
E.g.f.: (Sum_{p=2..6} (((-1)^p)*binomial(6, p)*hypergeom([(p-1)/2, p/2], [], 4*x)) - 5)/6! (cf. A090438).
From Amiram Eldar, Nov 03 2022: (Start)
Sum_{n>=3} 1/a(n) = -594 + 1800*Gamma - 1008*cosh(1) - 1800*CoshIntegral(1) + 912*sinh(1) + 1464*SinhIntegral(1).
Sum_{n>=3} (-1)^(n+1)/a(n) = 1554 + 1080*gamma - 1248*cos(1) - 1080*CosIntegral(1) + 240*sin(1) - 1416*SinIntegral(1). (End)

A114940 Decimal expansion of the infinite sum Sum_{k>=1} sin(k)/k!.

Original entry on oeis.org

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

Views

Author

Stefan Steinerberger, Feb 21 2006

Keywords

Comments

This is the imaginary part of exp(exp(i)), i the imaginary unit, where the real part is 1+A114941. - R. J. Mathar, Apr 11 2024

Examples

			1.279883001373022493908...
		

Crossrefs

Programs

  • Mathematica
    Sum[N[Sin[i], 400]/i!, {i, 1, 300}] (* This is accurate to 300 digits. *)
  • PARI
    suminf(k=1, sin(k)/k!) \\ Michel Marcus, Jul 19 2020

Formula

From Amiram Eldar, Jul 19 2020: (Start)
Equals e^cos(1) * sin(sin(1)).
Equals sin(sin(1)) * (cosh(cos(1)) + sinh(cos(1))).
Equals (-i)*(e^(e^i) - e^(e^(-i)))/2. (End)

A117017 Decimal expansion of (sine of 1 radian)^(1/2).

Original entry on oeis.org

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

Views

Author

Mohammad K. Azarian, Apr 15 2006

Keywords

Examples

			0.917317275978108081904271835360260308316831382531234230407306783565563168854...
		

Crossrefs

Cf. A049469.

Programs

  • Mathematica
    RealDigits[Sqrt[Sin[1]],10,120][[1]] (* Harvey P. Dale, Sep 29 2023 *)

Formula

A117017 = Sum_{n>=0} A008991(n)/A008992(n). - Johannes W. Meijer, Feb 10 2013

Extensions

Offset corrected by Mohammad K. Azarian, Dec 11 2008

A222131 Decimal expansion of the imaginary part of Pi^i, where i=sqrt(-1).

Original entry on oeis.org

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

Views

Author

Bruno Berselli, Feb 08 2013

Keywords

Examples

			0.910598499212614707060044514236877474514929053377520207196164279559...
		

Crossrefs

Cf. A053510, A049469 (imaginary part of e^i), A222130 (real part of Pi^i).

Programs

  • Mathematica
     RealDigits[Im[Pi^I], 10, 90][[1]] (* or *) RealDigits[Sin[Log[Pi]], 10, 90][[1]]
  • Maxima
    fpprec:90; ev(bfloat(imagpart(%pi^%i)));

Formula

Equals sin(log(Pi)) = (Pi^i-1/Pi^i)/(2*i).

A280189 Version of sexagesimal expansion of sine of one degree given by the Persian mathematician Al-Kashi in the 15th Century.

Original entry on oeis.org

1, 2, 49, 43, 11, 14, 44, 16, 26, 17
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

A334378 Decimal expansion of Sum_{k>=0} 1/((2*k+1)!)^2.

Original entry on oeis.org

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

Views

Author

Ilya Gutkovskiy, Apr 25 2020

Keywords

Examples

			1/1!^2 + 1/3!^2 + 1/5!^2 + 1/7!^2 + ... = 1.027847261597415799692...
Continued fraction: 1 + 1/(36 - 36/(401 - 400/(1765 - ... - P(n-1)/((P(n) + 1) - ... )))), where P(n) = (2*n*(2*n + 1))^2 for n >= 1. - _Peter Bala_, Feb 22 2024
		

Crossrefs

Programs

  • Mathematica
    RealDigits[(BesselI[0, 2] - BesselJ[0, 2])/2, 10, 110] [[1]]
  • PARI
    suminf(k=0, 1/((2*k+1)!)^2) \\ Michel Marcus, Apr 26 2020
    
  • PARI
    (besseli(0,2) - besselj(0,2))/2 \\ Michel Marcus, Apr 26 2020

Formula

Equals (BesselI(0,2) - BesselJ(0,2))/2.

A068116 Continued fraction expansion for sin(1).

Original entry on oeis.org

0, 1, 5, 3, 4, 19, 2, 2, 2, 2, 7, 2, 2, 1, 136, 3, 20, 3, 1, 3, 2, 1, 1, 1, 1, 10, 11, 2, 9, 54, 3, 1, 16, 1, 1, 1, 1, 1, 4, 4, 1, 2, 1, 1, 3, 11, 1, 1, 25, 1, 1, 14, 3, 1, 2, 1, 2, 2, 2, 2, 1, 2, 9, 6, 1, 4, 4, 1, 5, 1, 14, 6, 2, 12, 1, 1, 1, 1, 2, 11, 15, 152
Offset: 0

Views

Author

Benoit Cloitre, Mar 13 2002

Keywords

Crossrefs

Cf. A049469 (decimal expansion), A068115.

Programs

  • Magma
    SetDefaultRealField(RealField(100)); ContinuedFraction(Sin(1)); // G. C. Greubel, Nov 30 2018
    
  • Mathematica
    ContinuedFraction[Sin[1],90] (* Harvey P. Dale, Sep 16 2011 *)
  • PARI
    default(realprecision, 100); contfrac(sin(1)) \\ G. C. Greubel, Nov 30 2018
    
  • Sage
    continued_fraction_list(sin(1), nterms=100) # G. C. Greubel, Nov 30 2018

Extensions

Offset changed by Andrew Howroyd, Aug 05 2024

A068878 Denominators of nonzero terms in the expansion of sin(x)+exp(x)-1-2*x.

Original entry on oeis.org

2, 24, 60, 720, 40320, 181440, 3628800, 479001600, 3113510400, 87178291200, 20922789888000, 177843714048000, 6402373705728000, 2432902008176640000, 25545471085854720000, 1124000727777607680000, 620448401733239439360000, 7755605021665492992000000, 403291461126605635584000000
Offset: 1

Views

Author

Benoit Cloitre, Mar 29 2002

Keywords

Crossrefs

Programs

  • Mathematica
    Select[CoefficientList[Series[Sin[x] + Exp[x] - 1 - 2 x, {x, 0, 25}], x], # != 0 &] // Denominator
    (* second program: *)
    a[n_] := Switch[Mod[n, 3], 1, ((4*n+2)/3)!, 2, ((4*n+4)/3)!, 0, ((4*n+3)/3)!/2]; Array[a, 17] (* Amiram Eldar, May 05 2025 *)

Formula

a(3k+1)=(4k+2)!, a(3k+2)=(4k+4)!, a(3k+3)=(4k+5)!/2.
Sum_{n>=1} 1/a(n) = e + sin(1) - 3 = A001113 + A049469 - 3 = A348374 - 3. - Amiram Eldar, May 05 2025

Extensions

Name clarified by Sean A. Irvine, Mar 19 2024
More terms from Amiram Eldar, May 05 2025

A085662 Decimal expansion of sin(sin(1)).

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, Jul 15 2003

Keywords

Examples

			0.74562414166555788889315107043038379205029164661536...
		

Crossrefs

Cf. A049469.

Programs

A114941 Decimal expansion of the infinite sum Sum_{k>=1} cos(k)/k!.

Original entry on oeis.org

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

Views

Author

Stefan Steinerberger, Feb 21 2006

Keywords

Examples

			0.143835643791640325906...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[Sum[N[Cos[i],400]/i!, {i,1,300}]][[1]] (*which is accurate to 300 digits*) (* corrected by Harvey P. Dale, Nov 29 2011 *)
  • PARI
    suminf(k=1, cos(k)/k!) \\ Michel Marcus, Jul 19 2020

Formula

From Amiram Eldar, Jul 19 2020: (Start)
Equals e^cos(1) * cos(sin(1)) - 1.
Equals cos(sin(1)) * (cosh(cos(1)) + sinh(cos(1))) - 1.
Equals (e^(e^i) + e^(e^(-i)))/2 - 1. (End)
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