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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A154246 a(n) = ( (5 + sqrt(7))^n - (5 - sqrt(7))^n )/(2*sqrt(7)).

Original entry on oeis.org

1, 10, 82, 640, 4924, 37720, 288568, 2206720, 16872976, 129008800, 986374432, 7541585920, 57661119424, 440862647680, 3370726327168, 25771735613440, 197044282245376, 1506551581411840, 11518718733701632, 88069258871603200
Offset: 1

Views

Author

Al Hakanson (hawkuu(AT)gmail.com), Jan 05 2009

Keywords

Comments

Second binomial transform of A086901 without initial term 1.
Lim_{n -> infinity} a(n)/a(n-1) = 5 + sqrt(7) = 7.6457513110....

Crossrefs

Cf. A010465 (decimal expansion of square root of 7), A086901.

Programs

  • Magma
    Z:=PolynomialRing(Integers()); N:=NumberField(x^2-7); S:=[((5+r)^n-(5-r)^n)/(2*r): n in [1..25]]; [Integers()!S[j]: j in [1..#S]]; // Klaus Brockhaus, Jan 07 2009
    
  • Magma
    I:=[1,10]; [n le 2 select I[n] else 10*Self(n-1)-18*Self(n-2): n in [1..25]]; // Vincenzo Librandi, Sep 08 2016
    
  • Mathematica
    Table[Simplify[((5+Sqrt[7])^n -(5-Sqrt[7])^n)/(2*Sqrt[7])], {n,1,25}] (* or *) LinearRecurrence[{10, -18}, {1, 10}, 25] (* G. C. Greubel, Sep 07 2016 *)
  • PARI
    my(x='x+O('x^25)); Vec(x/(1-10*x+18*x^2)) \\ G. C. Greubel, May 31 2019
  • Sage
    [lucas_number1(n,10,18) for n in range(1, 25)] # Zerinvary Lajos, Apr 26 2009
    

Formula

From Philippe Deléham, Jan 06 2009: (Start)
a(n) = 10*a(n-1) - 18*a(n-2) for n > 1, with a(0)=0, a(1)=1.
G.f.: x/(1 - 10*x + 18*x^2). (End)
E.g.f.: (1/sqrt(7))*exp(5*x)*sinh(sqrt(7)*x). - G. C. Greubel, Sep 07 2016

Extensions

Extended beyond a(7) by Klaus Brockhaus, Jan 07 2009
Edited by Klaus Brockhaus, Oct 06 2009

A154247 a(n) = ( (6 + sqrt(7))^n - (6 - sqrt(7))^n )/(2*sqrt(7)).

Original entry on oeis.org

1, 12, 115, 1032, 9049, 78660, 681499, 5896848, 50998705, 440975868, 3812747971, 32964675480, 285006414601, 2464101386292, 21304030612075, 184189427142432, 1592456237959009, 13767981468377580, 119034546719719699
Offset: 1

Views

Author

Al Hakanson (hawkuu(AT)gmail.com), Jan 05 2009

Keywords

Comments

Lim_{n -> infinity} a(n)/a(n-1) = 6 + sqrt(7) = 8.6457513110....

Crossrefs

Cf. A010465 (decimal expansion of square root of 7).

Programs

  • Magma
    Z:=PolynomialRing(Integers()); N:=NumberField(x^2-7); S:=[ ((6+r)^n-(6-r)^n)/(2*r): n in [1..19] ]; [ Integers()!S[j]: j in [1..#S] ]; // Klaus Brockhaus, Jan 07 2009
    
  • Magma
    I:=[1,12]; [n le 2 select I[n] else 12*Self(n-1)-29*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Sep 08 2016
    
  • Mathematica
    Join[{a=1,b=12},Table[c=12*b-29*a;a=b;b=c,{n,60}]] (* Vladimir Joseph Stephan Orlovsky, Jan 31 2011 *)
    With[{c=Sqrt[7]},Simplify/@Table[((6+c)^n-(6-c)^n)/(2c),{n,20}]] (* or *) LinearRecurrence[{12,-29},{1,12},20] (* Harvey P. Dale, Mar 02 2012 *)
  • Sage
    [lucas_number1(n,12,29) for n in range(1, 20)] # Zerinvary Lajos, Apr 27 2009

Formula

From Philippe Deléham, Jan 06 2009: (Start)
a(n) = 12*a(n-1) - 29*a(n-2) for n > 1, with a(0)=0, a(1)=1.
G.f.: x/(1 - 12*x + 29*x^2). (End)
E.g.f.: sinh(sqrt(7)*x)*exp(6*x)/sqrt(7). - Ilya Gutkovskiy, Sep 08 2016

Extensions

Extended beyond a(7) by Klaus Brockhaus, Jan 07 2009
Edited by Klaus Brockhaus, Oct 06 2009

A154249 a(n) = ( (8 + sqrt(7))^n - (8 - sqrt(7))^n )/(2*sqrt(7)).

Original entry on oeis.org

1, 16, 199, 2272, 25009, 270640, 2904727, 31049152, 331216993, 3529670224, 37595354983, 400334476960, 4262416397329, 45379597170544, 483115820080951, 5143216082574208, 54753855576573121, 582898372518440080
Offset: 1

Views

Author

Al Hakanson (hawkuu(AT)gmail.com), Jan 05 2009

Keywords

Comments

lim_{n -> infinity} a(n)/a(n-1) = 8 + sqrt(7) = 10.6457513110....

Crossrefs

Cf. A010465 (decimal expansion of square root of 7).

Programs

  • Magma
    Z:=PolynomialRing(Integers()); N:=NumberField(x^2-7); S:=[ ((8+r)^n-(8-r)^n)/(2*r): n in [1..18] ]; [ Integers()!S[j]: j in [1..#S] ]; // Klaus Brockhaus, Jan 07 2009
  • Maple
    seq(expand((8+sqrt(7))^n-(8-sqrt(7))^n)/sqrt(28), n = 1 .. 20); # Emeric Deutsch, Jan 08 2009
  • Mathematica
    Join[{a=1,b=16},Table[c=16*b-57*a;a=b;b=c,{n,40}]] (* Vladimir Joseph Stephan Orlovsky, Feb 08 2011 *)
    LinearRecurrence[{16,-57},{1,16},25] (* or *) Table[( (8 + sqrt(7))^n - (8 - sqrt(7))^n )/(2*sqrt(7)), {n,1,25}] (* G. C. Greubel, Sep 08 2016 *)

Formula

From Philippe Deléham, Jan 06 2009: (Start)
a(n) = 16*a(n-1)-57*a(n-2) for n>1, with a(0)=0, a(1)=1.
G.f.: x/(1 - 16*x + 57*x^2). (End)
E.g.f.: (1/sqrt(7))*exp(8*x)*sinh(sqrt(7)*x). - G. C. Greubel, Sep 08 2016

Extensions

Extended by Emeric Deutsch and Klaus Brockhaus, Jan 08 2009
Edited by Klaus Brockhaus, Oct 06 2009

A154250 a(n) = ( (9 + sqrt(7))^n - (9 - sqrt(7))^n )/(2*sqrt(7)).

Original entry on oeis.org

1, 18, 250, 3168, 38524, 459000, 5411224, 63436032, 741418000, 8651257632, 100857705376, 1175245632000, 13690951178176, 159468944439168, 1857310612720000, 21630889140461568, 251915019187028224
Offset: 1

Views

Author

Al Hakanson (hawkuu(AT)gmail.com), Jan 05 2009

Keywords

Comments

lim_{n -> infinity} a(n)/a(n-1) = 9 + sqrt(7) = 11.6457513110....

Crossrefs

Cf. A010465 (decimal expansion of square root of 7).

Programs

  • Magma
    Z:=PolynomialRing(Integers()); N:=NumberField(x^2-7); S:=[ ((9+r)^n-(9-r)^n)/(2*r): n in [1..17] ]; [ Integers()!S[j]: j in [1..#S] ]; // Klaus Brockhaus, Jan 07 2009
  • Mathematica
    Join[{a=1,b=18},Table[c=18*b-74*a;a=b;b=c,{n,40}]] (* Vladimir Joseph Stephan Orlovsky, Feb 09 2011*)
    LinearRecurrence[{18,-74},{1,18},20] (* Harvey P. Dale, Feb 16 2014 *)

Formula

From Philippe Deléham, Jan 06 2009: (Start)
a(n) = 18*a(n-1) - 74*a(n-2) for n>1, with a(0)=0, a(1)=1.
G.f.: x/(1 - 18*x + 74*x^2). (End)

Extensions

Extended beyond a(7) by Klaus Brockhaus, Jan 07 2009
Edited by Klaus Brockhaus, Oct 06 2009

A171545 Decimal expansion of sqrt(2/7).

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Dec 11 2009

Keywords

Comments

The absolute value of the Clebsch-Gordan coupling coefficient = <2 3/2 ; 0 -3/2 | 7/2 -3/2>.

Examples

			sqrt(2/7) = sqrt(14)/7 = 0.53452248382484876936910696175950...
		

Programs

Formula

A171547 Decimal expansion of sqrt(3/14).

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Dec 11 2009

Keywords

Comments

The absolute value of the Clebsch-Gordan coupling coefficient = <2 2 ; -2 0 | 4 -2>.

Examples

			sqrt(3/14) = sqrt(42)/14 = 0.462910049886275730783283388291999761264...
		

Crossrefs

Programs

  • Mathematica
    RealDigits[Sqrt[3/14],10,120][[1]] (* Harvey P. Dale, Sep 23 2011 *)

Formula

A171548 Decimal expansion of 2*sqrt(2/35).

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Dec 11 2009

Keywords

Comments

The absolute value of the Clebsch-Gordan coupling coefficient < j1 j2; m1 m2 | J M > = < 2 2; -1 1 | 4 0 >.

Examples

			Sqrt(8/35) = 2*sqrt(70)/35 = 0.478091443733757455987526871877249993..
		

Crossrefs

Programs

  • Magma
    SetDefaultRealField(RealField(100)); 2*Sqrt(2/35); // G. C. Greubel, Oct 02 2018
  • Mathematica
    RealDigits[2*Sqrt[2/35], 10, 100][[1]] (* G. C. Greubel, Oct 02 2018 *)
  • PARI
    2*sqrt(2/35) \\ Michel Marcus, Dec 23 2015
    

Formula

A176054 Decimal expansion of (7+3*sqrt(7))/7.

Original entry on oeis.org

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

Views

Author

Klaus Brockhaus, Apr 07 2010

Keywords

Comments

Continued fraction expansion of (7+3*sqrt(7))/7 is A010697.

Examples

			(7+3*sqrt(7))/7 = 2.13389341902768168164...
		

Crossrefs

Cf. A010465 (decimal expansion of sqrt(7)), A010697 (repeat 2, 7).

A176434 Decimal expansion of (7+3*sqrt(7))/2.

Original entry on oeis.org

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

Views

Author

Klaus Brockhaus, Apr 19 2010

Keywords

Comments

Continued fraction expansion of (7+3*sqrt(7))/2 is A010697 preceded by 7.

Examples

			(7+3*sqrt(7))/2 = 7.46862696659688588575...
		

Crossrefs

Cf. A010465 (decimal expansion of sqrt(7)), A010697 (repeat 2, 7).

A177016 Decimal expansion of sqrt(16926).

Original entry on oeis.org

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

Views

Author

Klaus Brockhaus, May 01 2010

Keywords

Comments

Continued fraction expansion of sqrt(16926) is 130 followed by (repeat 10, 260).
sqrt(16926) = sqrt(2)*sqrt(3)*sqrt(7)*sqrt(13)*sqrt(31).

Examples

			sqrt(16926) = 130.09996156801891999550...
		

Crossrefs

Cf. A002193 (decimal expansion of sqrt(2)), A002194 (decimal expansion of sqrt(3)), A010465 (decimal expansion of sqrt(7)), A010470 (decimal expansion of sqrt(13)), A010486 (decimal expansion of sqrt(31)), A177015 (decimal expansion of (124+sqrt(16926))/25).
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