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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A036827 a(n) = 26 + 2^(n+1)*(-13 +9*n -3*n^2 +n^3).

Original entry on oeis.org

0, 2, 34, 250, 1274, 5274, 19098, 63002, 194074, 567322, 1591322, 4317210, 11395098, 29392922, 74350618, 184942618, 453378074, 1097334810, 2626158618, 6222250010, 14610858010, 34032582682, 78693531674, 180757725210, 412685959194
Offset: 0

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Author

Keywords

Examples

			a(3) = 2^0*0^3 + 2^1*1^3 + 2^2*2^3 + 2^3*3^3 = 250.
		

References

  • M. Petkovsek et al., A=B, Peters, 1996, p. 97.

Crossrefs

Cf. A059841 (p=0,q=-1), A130472 (p=1,q=-1), A089594 (p=2,q=-1), A232599 (p=3,q=-1), A126646 (p=0,q=2), A036799 (p=1,q=2), A036800 (p=2,q=2), this sequence (p=3,q=2), A077925 (p=0,q=-2), A232600 (p=1,q=-2), A232601 (p=2,q=-2), A232602 (p=3,q=-2), A232603 (p=2,q=-1/2), A232604 (p=3,q=-1/2).

Programs

  • Haskell
    a036827 n = 2^(n+1) * (n^3 - 3*n^2 + 9*n - 13) + 26
    -- Reinhard Zumkeller, May 24 2012
    
  • Magma
    [2*(13 + 2^n*(-13 +9*n -3*n^2 +n^3)): n in [0..35]]; // G. C. Greubel, Mar 31 2021
    
  • Maple
    A036827:= n-> 2*(13 + 2^n*(-13 +9*n -3*n^2 +n^3)); seq(A026827(n), n=0..30); # G. C. Greubel, Mar 31 2021
  • Mathematica
    Table[26 +2^(n+1)(-13 +9n -3n^2 +n^3), {n, 0, 30}] (* or *) LinearRecurrence[ {9, -32, 56, -48, 16}, {0, 2, 34, 250, 1274}, 31] (* Harvey P. Dale, Dec 15 2011 *)
  • PARI
    a(n)=26+2^(n+1)*(-13+9*n-3*n^2+n^3) \\ Charles R Greathouse IV, Oct 07 2015
    
  • Sage
    [2*(13 + 2^n*(-13 +9*n -3*n^2 +n^3)) for n in (0..35)] # G. C. Greubel, Mar 31 2021

Formula

a(n) = Sum_{k=0..n} 2^k*k^3. - Benoit Cloitre, Jun 11 2003
G.f.: 2*x*(1 +8*x +4*x^2)/((1-x)*(1-2*x)^4). - Maksym Voznyy (voznyy(AT)mail.ru), Jul 26 2009
a(n) = 9*a(n-1) -32*a(n-2) +56*a(n-3) -48*a(n-4) +16*a(n-5) for n>4 with a(0)=0, a(1)=2, a(2)=34, a(3)=250, a(4)=1274. - Harvey P. Dale, Dec 15 2011
a(n) = Sum_{k=0..n} Sum_{i=0..n} k^3 * C(k,i). - Wesley Ivan Hurt, Sep 21 2017
E.g.f.: 2 (13*exp(x) + (-13 +14*x +8*x^3)*exp(2*x)). - G. C. Greubel, Mar 31 2021

A014992 a(n) = (1 - (-10)^n)/11.

Original entry on oeis.org

1, -9, 91, -909, 9091, -90909, 909091, -9090909, 90909091, -909090909, 9090909091, -90909090909, 909090909091, -9090909090909, 90909090909091, -909090909090909, 9090909090909091, -90909090909090909
Offset: 1

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Author

Keywords

Comments

q-integers for q = -10.

Crossrefs

Programs

  • Magma
    I:=[1, -9]; [n le 2 select I[n] else -9*Self(n-1) +10*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Oct 22 2012
    
  • Maple
    a:=n->sum ((-10)^j, j=0..n): seq(a(n), n=0..25); # Zerinvary Lajos, Dec 16 2008
  • Mathematica
    CoefficientList[Series[1/((1 - x)*(1 + 10*x)), {x, 0, 30}], x] (* Vincenzo Librandi, Oct 22 2012 *)
  • PARI
    for(n=1, 30, print1((1-(-10)^n)/11, ", ")) \\ G. C. Greubel, May 26 2018
  • Sage
    [gaussian_binomial(n,1,-10) for n in range(1,19)] # Zerinvary Lajos, May 28 2009
    

Formula

a(n) = a(n-1) + q^(n-1) = (q^n - 1) / (q - 1).
G.f.: x/((1 - x)*(1 + 10*x)). - Vincenzo Librandi, Oct 22 2012
a(n) = -9*a(n-1) + 10*a(n-2). - Vincenzo Librandi, Oct 22 2012
a(n) = (-1)^(n+1)*A015585(n). - R. J. Mathar, Oct 26 2015
E.g.f.: (exp(x) - exp(-10*x))/11. - G. C. Greubel, May 26 2018

Extensions

Better name from Ralf Stephan, Jul 14 2013

A077953 Expansion of 1/(1-x+2*x^2-2*x^3).

Original entry on oeis.org

1, 1, -1, -1, 3, 3, -5, -5, 11, 11, -21, -21, 43, 43, -85, -85, 171, 171, -341, -341, 683, 683, -1365, -1365, 2731, 2731, -5461, -5461, 10923, 10923, -21845, -21845, 43691, 43691, -87381, -87381, 174763, 174763, -349525, -349525, 699051, 699051, -1398101, -1398101, 2796203, 2796203, -5592405
Offset: 0

Views

Author

N. J. A. Sloane, Nov 17 2002, Jun 17 2007

Keywords

Comments

Essentially the same as A077980.

Crossrefs

Cf. A077980.
Cf. A007420, A077925. - Reinhard Zumkeller, Oct 07 2008

Programs

  • GAP
    a:=[1,1,-1];; for n in [4..50] do a[n]:=a[n-1]-2*a[n-2]+2*a[n-3]; od; a; # G. C. Greubel, Aug 07 2019
  • Magma
    R:=PowerSeriesRing(Integers(), 50); Coefficients(R!( 1/(1-x+2*x^2-2*x^3) )); // G. C. Greubel, Aug 07 2019
    
  • Maple
    seq(coeff(series(1/(1-x+2*x^2-2*x^3), x, n+1), x, n), n = 0 .. 40); # G. C. Greubel, Aug 07 2019
  • Mathematica
    CoefficientList[Series[1/(1-x+2x^2-2x^3),{x,0,50}],x] (* or *) LinearRecurrence[{1,-2,2},{1,1,-1},50] (* Harvey P. Dale, Aug 27 2014 *)
  • PARI
    Vec(1/(1-x+2*x^2-2*x^3)+O(x^50)) \\ Charles R Greathouse IV, Sep 25 2012
    
  • Sage
    (1/(1-x+2*x^2-2*x^3)).series(x, 50).coefficients(x, sparse=False) # G. C. Greubel, Aug 07 2019
    

Formula

From Reinhard Zumkeller, Oct 07 2008: (Start)
a(n+1) = a(n) - 2*a(n-1) + 2*a(n-2).
a(n) = A077925(floor(n/2)-1) for n>1. (End)

A014991 a(n) = (1 - (-9)^n)/10.

Original entry on oeis.org

1, -8, 73, -656, 5905, -53144, 478297, -4304672, 38742049, -348678440, 3138105961, -28242953648, 254186582833, -2287679245496, 20589113209465, -185302018885184, 1667718169966657, -15009463529699912
Offset: 1

Views

Author

Keywords

Comments

q-integers for q = -9.

Crossrefs

Programs

  • Magma
    I:=[1,-8]; [n le 2 select I[n] else -8*Self(n-1)+9*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Oct 22 2012
    
  • Maple
    a:=n->sum ((-9)^j, j=0..n): seq(a(n), n=0..25); # Zerinvary Lajos, Dec 16 2008
  • Mathematica
    ((-9)^Range[30]-1)/-10 (* or *) LinearRecurrence[{-8,9},{1,-8},30] (* Harvey P. Dale, Aug 08 2011 *)
    CoefficientList[Series[1/((1 - x)*(1 + 9*x)), {x, 0, 30}], x]; (* Vincenzo Librandi, Oct 22 2012 *)
  • PARI
    for(n=1,30, print1((1-(-9)^n)/10, ", ")) \\ G. C. Greubel, May 26 2018
  • Sage
    [gaussian_binomial(n,1,-9) for n in range(1,19)] # Zerinvary Lajos, May 28 2009
    

Formula

a(n) = a(n-1) + q^(n-1) = (q^n - 1) / (q - 1).
a(0)=1, a(1)=-8, a(n) = -8*a(n-1) + 9*a(n-2). - Harvey P. Dale, Aug 08 2011
G.f.: x/((1 - x)*(1 + 9*x)). - Vincenzo Librandi, Oct 22 2012
E.g.f.: (exp(x) - exp(-9*x))/10. - G. C. Greubel, May 26 2018

Extensions

Better name from Ralf Stephan, Jul 14 2013

A014993 a(n) = (1 - (-11)^n)/12.

Original entry on oeis.org

1, -10, 111, -1220, 13421, -147630, 1623931, -17863240, 196495641, -2161452050, 23775972551, -261535698060, 2876892678661, -31645819465270, 348104014117971, -3829144155297680, 42120585708274481
Offset: 1

Views

Author

Keywords

Comments

q-integers for q = -11.

Crossrefs

Programs

  • Magma
    I:=[1, -10]; [n le 2 select I[n] else -10*Self(n-1) +11*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Oct 22 2012
    
  • Maple
    a:=n->sum ((-11)^j, j=0..n): seq(a(n), n=0..25); # Zerinvary Lajos, Dec 16 2008
  • Mathematica
    LinearRecurrence[{-10, 11}, {1, -10}, 40] (* Vincenzo Librandi, Oct 22 2012 *)
  • PARI
    for(n=1,30, print1((1-(-11)^n)/12, ", ")) \\ G. C. Greubel, May 26 2018
  • Sage
    [gaussian_binomial(n,1,-11) for n in range(1,18)] # Zerinvary Lajos, May 28 2009
    

Formula

a(n) = a(n-1) + q^{(n-1)} = {(q^n - 1) / (q - 1)}.
G.f.: x/((1 - x)*(1 + 11*x)). - Vincenzo Librandi, Oct 22 2012
a(n) = -10*a(n-1) + 11*a(n-2). - Vincenzo Librandi, Oct 22 2012
E.g.f.: (exp(x) - exp(-11*x))/12. - G. C. Greubel, May 26 2018

Extensions

Better name from Ralf Stephan, Jul 14 2013

A140431 2*A094555(n).

Original entry on oeis.org

0, 2, 2, 12, 22, 92, 222, 772, 2102, 6732, 19342, 59732, 175782, 534172, 1588862, 4793892, 14327062, 43090412, 129052782, 387595252, 1161911942, 3487483452, 10458955102, 31383855812, 94137586422, 282440721292, 847266239822
Offset: 0

Views

Author

Paul Curtz, Jun 19 2008

Keywords

Formula

b(n) = A091002(n-1); b(n+1)-3b(n)= A077925(n-2), where b(n)=floor(a(n)/10).
a(n) = (1-(-2)^n+3^n)/3 for n>0. a(n) = 2*a(n-1)+5*a(n-2)-6*a(n-3) for n>3. G.f.: 2*x*(1-x-x^2)/((1-x)*(1+2*x)*(1-3*x)). [Colin Barker, Sep 21 2012]

Extensions

Edited and extended by R. J. Mathar, Aug 02 2008

A166035 a(n) = (3^n+6*(-4)^n)/7.

Original entry on oeis.org

1, -3, 15, -51, 231, -843, 3615, -13731, 57111, -221883, 907215, -3569811, 14456391, -57294123, 230770815, -918300291, 3687550071, -14707153563, 58957754415, -235443597171, 942936650151, -3768259816203, 15083499618015
Offset: 0

Views

Author

Philippe Deléham, Oct 05 2009

Keywords

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{-1, 12}, {1, -3}, 100] (* G. C. Greubel, Apr 24 2016 *)
  • PARI
    a(n)= (3^n+6*(-4)^n)/7;
    for(n=0,33,print1(a(n),", "));

Formula

a(n) = -a(n-1) + 12*a(n-2), a(0) = 1, a(1) = -3, for n>1.
a(n) = Sum_{0<=k<=n} A112555(n,k)*(-4)^k.
G.f.: (1-2x)/(1+x-12x^2).
E.g.f.: (1/7)*(exp(3*x) + 6*exp(-4*x)). - G. C. Greubel, Apr 24 2016

Extensions

a(5) corrected by Tilman Neumann, Dec 31 2010

A166036 a(n) = (4^n+8*(-5)^n)/9.

Original entry on oeis.org

1, -4, 24, -104, 584, -2664, 14344, -67624, 354504, -1706984, 8797064, -42936744, 218878024, -1077612904, 5455173384, -27007431464, 136110899144, -676259528424, 3398477511304, -16923668079784
Offset: 0

Views

Author

Philippe Deléham, Oct 05 2009

Keywords

Crossrefs

Programs

  • Mathematica
    Table[(4^n+8(-5)^n)/9,{n,0,30}] (* or *) LinearRecurrence[{-1,20},{1,-4},30] (* Harvey P. Dale, Mar 05 2016 *)
  • PARI
    vector(100, n, n--; (4^n+8*(-5)^n)/9) \\ Altug Alkan, Apr 24 2016

Formula

a(n) = -a(n-1) + 20*a(n-2), a(0) = 1, a(1) = -4, for n>1.
a(n) = Sum_{k=0..n} A112555(n,k)*(-5)^k.
G.f.: (1-3x)/(1+x-20x^2).
E.g.f.: (1/9)*(exp(4*x) + 8*exp(-5*x)). - G. C. Greubel, Apr 24 2016

A077898 Expansion of (1 - x)^(-1)/(1 + x - 2*x^2).

Original entry on oeis.org

1, 0, 3, -2, 9, -12, 31, -54, 117, -224, 459, -906, 1825, -3636, 7287, -14558, 29133, -58248, 116515, -233010, 466041, -932060, 1864143, -3728262, 7456549, -14913072, 29826171, -59652314, 119304657, -238609284, 477218599, -954437166, 1908874365, -3817748696, 7635497427
Offset: 0

Views

Author

N. J. A. Sloane, Nov 17 2002

Keywords

Comments

Partial sums of A077925 (signed Jacobsthal numbers). - Paul Barry, Aug 26 2003
The generalized (3,-2)-Padovan sequence p(3,-2;n). See the W. Lang link under A000931 with (A,B)=(3,-2). - Wolfdieter Lang, Jun 28 2010

Examples

			(3,-2)-Padovan combinatorics from the (3,2)-Morse code with weights -2 and 3 for 3-lines -- and 2-lines -, respectively (see the W. Lang link under A000931). n=5: two codes - -- and -- - with the weights (3^1)*(-2)^1 and (-2)^1*3^1, respectively, adding up to 2*(3)(-2) = -12 = a(5). - _Wolfdieter Lang_, Jun 28 2010
		

Crossrefs

Programs

Formula

G.f.: (1-x)^(-1)/(1+x-2*x^2).
a(n) = Sum_{k=0..n} Sum_{j=0..k} Sum_{i=0..j} binomial(j, i)*(-3)^i. - Paul Barry, Aug 26 2003
a(n) = (-1)^n * A053088(n). - R. J. Mathar, Aug 30 2008
From Colin Barker, Apr 21 2016: (Start)
a(n) = 3*a(n-2) - 2*a(n-3) for n>2.
a(n) = (5+(-1)^n*2^(2+n)+3*n)/9. (End)
E.g.f.: (4*exp(-2*x) + (5 + 3*x)*exp(x))/9. - Ilya Gutkovskiy, Apr 21 2016
a(n) = Sum_{k=0..n} (n+1-k)*(-2)^k. - Bruno Berselli, May 15 2018

A015000 q-integers for q=-13.

Original entry on oeis.org

1, -12, 157, -2040, 26521, -344772, 4482037, -58266480, 757464241, -9847035132, 128011456717, -1664148937320, 21633936185161, -281241170407092, 3656135215292197, -47529757798798560, 617886851384381281
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Magma
    I:=[1,-12]; [n le 2 select I[n] else -12*Self(n-1)+13*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Oct 22 2012
    
  • Maple
    a:=n->sum ((-13)^j, j=0..n-1): seq(a(n), n=0..20); # Zerinvary Lajos, Dec 16 2008
  • Mathematica
    QBinomial[Range[20],1,-13] (* Harvey P. Dale, May 02 2012 *)
    LinearRecurrence[{-12, 13}, {1, -12}, 30] (* Vincenzo Librandi, Oct 22 2012 *)
  • PARI
    for(n=1, 30, print1((1-(-13)^n)/14, ", ")) \\ G. C. Greubel, May 26 2018
  • Sage
    [gaussian_binomial(n,1,-13) for n in range(1,18)] # Zerinvary Lajos, May 28 2009
    

Formula

a(n) = a(n-1) + q^(n-1) = (q^n - 1) / (q - 1), with q=-13.
a(n) = Sum_{j=0..n-1} (-13)^j. - Zerinvary Lajos, Dec 16 2008
G.f.: x/((1 - x)*(1 + 13*x)). - Vincenzo Librandi, Oct 22 2012
a(n) = -12*a(n-1) + 13*a(n-2). - Vincenzo Librandi, Oct 22 2012
From G. C. Greubel, May 26 2018: (Start)
a(n) = (1 - (-13)^n)/14.
E.g.f.: (exp(x) - exp(-13*x))/14. (End)

Extensions

Edited by N. J. A. Sloane, Jan 13 2009 at the suggestion of R. J. Mathar
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