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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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

A091004 Expansion of x*(1-x)/((1-2*x)*(1+3*x)).

Original entry on oeis.org

0, 1, -2, 8, -20, 68, -188, 596, -1724, 5300, -15644, 47444, -141308, 425972, -1273820, 3829652, -11472572, 34450484, -103285916, 309988820, -929704316, 2789637236, -8367863132, 25105686548, -75312865340, 225946984628, -677824176668, 2033506084436
Offset: 0

Views

Author

Paul Barry, Dec 13 2003

Keywords

Comments

Inverse binomial transform of A091001.

Crossrefs

Programs

  • GAP
    Concatenation([0], List([1..30], n -> (3*2^n - 8*(-3)^n)/30)); # G. C. Greubel, Feb 01 2019
  • Magma
    [0] cat [(3*2^n - 8*(-3)^n)/30: n in [1..30]]; // G. C. Greubel, Feb 01 2019
    
  • Mathematica
    CoefficientList[Series[x(1-x)/((1-2x)(1+3x)), {x, 0, 30}], x] (* Wesley Ivan Hurt, Jan 17 2017 *)
    Join[{0}, LinearRecurrence[{-1, 6}, {1, -2}, 30]] (* G. C. Greubel, Feb 01 2019 *)
  • PARI
    vector(30, n, n--; (3*2^n - 8*(-3)^n + 5*0^n)/30) \\ G. C. Greubel, Feb 01 2019
    
  • Sage
    [0] + [(3*2^n - 8*(-3)^n)/30 for n in (1..30)] # G. C. Greubel, Feb 01 2019
    

Formula

G.f.: x*(1-x)/((1-2*x)*(1+3*x)).
a(n) = (3*2^n - 8*(-3)^n + 5*0^n)/30.
2^n = A091003(n) + 3*a(n) + 6*A091005(n).
a(n+1) = Sum_{k=0..n} A112555(n,k)*(-3)^k. - Philippe Deléham, Sep 11 2009
E.g.f.: (3*exp(2*x) - 8*exp(-3*x) + 5)/30. - G. C. Greubel, Feb 01 2019

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

A166149 a(n) = (5^n + 10*(-6)^n)/11.

Original entry on oeis.org

1, -5, 35, -185, 1235, -6785, 43835, -247385, 1562435, -8983985, 55857035, -325376585, 2001087635, -11762385185, 71795014235, -424666569785, 2578516996835, -15318514090385, 92674023995435, -552229446706985
Offset: 0

Views

Author

Philippe Deléham, Oct 08 2009

Keywords

Comments

From Klaus Brockhaus, Oct 14 2009: (Start)
Fourth binomial transform of A014992.
Sixth binomial transform is A001020 preceded by 1.
Lim_{n -> infinity} a(n)/a(n-1) = -6. (End)

Crossrefs

Cf. A014992 (q-integers for q=-10), A001020 (powers of 11).

Programs

Formula

a(n) = 30*a(n-2)-a(n-1), a(0)= 1, a(1)= -5.
G.f.: (1-4x)/(1+x-30*x^2).
a(n) = Sum_{k=0..n} A112555(n,k)*(-6)^k.
E.g.f.: (1/11)*(exp(5*x) + 10*exp(-6*x)). - G. C. Greubel, May 01 2016

A080242 Table of coefficients of polynomials P(n,x) defined by the relation P(n,x) = (1+x)*P(n-1,x) + (-x)^(n+1).

Original entry on oeis.org

1, 1, 1, 1, 1, 2, 2, 1, 3, 4, 2, 1, 1, 4, 7, 6, 3, 1, 5, 11, 13, 9, 3, 1, 1, 6, 16, 24, 22, 12, 4, 1, 7, 22, 40, 46, 34, 16, 4, 1, 1, 8, 29, 62, 86, 80, 50, 20, 5, 1, 9, 37, 91, 148, 166, 130, 70, 25, 5, 1, 1, 10, 46, 128, 239, 314, 296, 200, 95
Offset: 0

Views

Author

Paul Barry, Feb 12 2003

Keywords

Comments

Values generate solutions to the recurrence a(n) = a(n-1) + k(k+1)* a(n-2), a(0)=1, a(1) = k(k+1)+1. Values and sequences associated with this table are included in A072024.

Examples

			Rows are {1}, {1,1,1}, {1,2,2}, {1,3,4,2,1}, {1,4,7,6,3}, ... This is the same as table A035317 with an extra 1 at the end of every second row.
Triangle begins
  1;
  1,  1,  1;
  1,  2,  2;
  1,  3,  4,  2,  1;
  1,  4,  7,  6,  3;
  1,  5, 11, 13,  9,  3,  1;
  1,  6, 16, 24, 22, 12,  4;
  1,  7, 22, 40, 46, 34, 16,  4,  1;
  1,  8, 29, 62, 86, 80, 50, 20,  5;
		

Crossrefs

Similar to the triangles A059259, A035317, A108561, A112555. Cf. A059260.
Cf. A001045 (row sums).

Programs

  • Mathematica
    Table[CoefficientList[Series[((1+x)^(n+2) -(-1)^n*x^(n+2))/(1+2*x), {x, 0, n+2}], x], {n, 0, 10}]//Flatten (* G. C. Greubel, Feb 18 2019 *)

Formula

Rows are generated by P(n,x) = ((x+1)^(n+2) - (-x)^(n+2))/(2*x+1).
The polynomials P(n,-x), n > 0, satisfy a Riemann hypothesis: their zeros lie on the vertical line Re x = 1/2 in the complex plane.
O.g.f.: (1+x*t+x^2*t)/((1+x*t)(1-t-x*t)) = 1 + (1+x+x^2)*t + (1+2x+2x^2)*t^2 + ... . - Peter Bala, Oct 24 2007
T(n,k) = if(k<=2*floor((n+1)/2), Sum_{j=0..floor((n+1)/2)} binomial(n-2j,k-2j), 0). - Paul Barry, Apr 08 2011 (This formula produces the odd numbered rows correctly, but not the even. - G. C. Greubel, Feb 22 2019)

A166152 a(n) = (6^n+12*(-7)^n)/13.

Original entry on oeis.org

1, -6, 48, -300, 2316, -14916, 112188, -738660, 5450556, -36474276, 265397628, -1797317220, 12944017596, -88431340836, 632080079868, -4346196394980, 30893559749436, -213433808338596, 1510963317814908
Offset: 0

Views

Author

Philippe Deléham, Oct 08 2009

Keywords

Crossrefs

Programs

Formula

a(n) = 42*a(n-2)-a(n-1), a(0)= 1, a(1)= -6, for n>1.
G.f.: (1-5x)/(1+x-42*x^2).
a(n)= Sum_{k, 0<=k<=n} A112555(n,k)*(-7)^k.
E.g.f.: (1/13)*(exp(6*x) + 12*exp(-7*x)). - G. C. Greubel, May 01 2016

A279006 Alternating Jacobsthal triangle read by rows (second version).

Original entry on oeis.org

1, 1, 1, 1, 0, 1, 1, -1, 1, 1, 1, -2, 2, 0, 1, 1, -3, 4, -2, 1, 1, 1, -4, 7, -6, 3, 0, 1, 1, -5, 11, -13, 9, -3, 1, 1, 1, -6, 16, -24, 22, -12, 4, 0, 1, 1, -7, 22, -40, 46, -34, 16, -4, 1, 1, 1, -8, 29, -62, 86, -80, 50, -20, 5, 0, 1, 1, -9, 37, -91, 148, -166, 130, -70, 25, -5, 1, 1
Offset: 0

Views

Author

N. J. A. Sloane, Dec 07 2016

Keywords

Examples

			Triangle begins:
  1,
  1,   1,
  1,   0,   1,
  1,  -1,   1,   1,
  1,  -2,   2,   0,   1,
  1,  -3,   4,  -2,   1,   1,
  1,  -4,   7,  -6,   3,   0,   1,
  1,  -5,  11, -13,   9,  -3,   1,   1,
  1,  -6,  16, -24,  22, -12,   4,   0,   1,
  ...
		

Crossrefs

See A112468, A112555 and A108561 for other versions.

Programs

  • Maple
    T := (n, k) -> local j; add((-1)^j*binomial(n-k-1+j, j), j = 0..k):
    seq(print(seq(T(n, k), k = 0..n)), n = 0..9);  # Peter Luschny, Aug 30 2024
  • Mathematica
    T[i_, i_] = T[, 0] = 1; T[i, j_] := T[i, j] = T[i-1, j] - T[i-1, j-1];
    Table[T[i, j], {i, 0, 11}, {j, 0, i}] // Flatten (* Jean-François Alcover, Sep 06 2018 *)
    T[n_, k_] := 2^k*Hypergeometric2F1[-n, -k, -k, 1/2]; Table[T[n, k], {n, 0, 11}, {k, 0, n}]//Flatten (* Detlef Meya, Aug 30 2024 *)
  • PARI
    \\ using arxiv (3.1) and (3.7) formulas where A is A220074 and B is this sequence
    A(i, j) = if ((i < 0), 0, if (j==0, 1, A(i - 1, j - 1) - A(i - 1, j))); \\ A220074
    B(i, j) = A(i, i-j);
    tabl(nn) = for (i=0, nn, for (j=0, i, print1(B(i,j), ", ")); print()); \\ Michel Marcus, Jun 17 2017

Formula

T(i, j) = A220074(i, i-j). See (3.7) in arxiv link. - Michel Marcus, Jun 17 2017
T(n, k) = 2^k*hypergeom([-n, -k], [-k], 1/2). - Detlef Meya, Aug 30 2024

Extensions

More terms from Michel Marcus, Jun 17 2017

A165405 a(0)=1, a(1)=3,a(n)=6*a(n-2)-a(n-1).

Original entry on oeis.org

1, 3, 3, 15, 3, 87, -69, 591, -1005, 4551, -10581, 37887, -101373, 328695, -936933, 2909103, -8530701, 25985319, -77169525, 233081439, -696098589, 2094587223, -6271178757, 18838702095, -56465774637, 169497987207, -508292635029
Offset: 0

Views

Author

Philippe Deléham, Sep 17 2009

Keywords

Comments

a(n)/a(n-1) tends to -3.

Programs

  • Mathematica
    nxt[{a_,b_}]:={b,6a-b}; NestList[nxt,{1,3},30][[;;,1]] (* or *) LinearRecurrence[{-1,6},{1,3},30] (* Harvey P. Dale, May 24 2024 *)

Formula

G.f.: (1+4x)/(1+x-6x^2). a(n)= Sum_{k, 0<=k<=n}A112555(n,k)*2^k.
a(n) = (6*2^n-(-3)^n)/5. [From Klaus Brockhaus, Sep 26 2009]

A165751 a(n) = 4 - 3*2^n.

Original entry on oeis.org

1, -2, -8, -20, -44, -92, -188, -380, -764, -1532, -3068, -6140, -12284, -24572, -49148, -98300, -196604, -393212, -786428, -1572860, -3145724, -6291452, -12582908, -25165820, -50331644, -100663292, -201326588, -402653180, -805306364, -1610612732, -3221225468
Offset: 0

Views

Author

Philippe Deléham, Sep 26 2009

Keywords

Crossrefs

Cf. A131128.

Programs

  • Mathematica
    Table[4 - 3*2^n, {n, 0, 50}] (* or *) LinearRecurrence[{3,-2}, {1,-2}, 50] (* G. C. Greubel, Apr 07 2016 *)
  • PARI
    my(x='x+O('x^99)); Vec((1-5*x)/(1-3*x+2*x^2)) \\ Altug Alkan, Apr 07 2016

Formula

a(n) = 2*a(n-1) - 4, a(0)=1.
a(n) = Sum_{0<=k<=n} A112555(n,k)*(-3)^(n-k).
G.f.: (1-5x)/(1-3x+2x^2).
From G. C. Greubel, Apr 07 2016: (Start)
a(n) = 3*a(n-1) - 2*a(n-2).
E.g.f.: 4*exp(x) - 3*exp(2*x). (End)
a(n) = -A131128(n) for n>=1. - R. J. Mathar, Feb 27 2019

A165759 a(n) = (7-4*7^n)/3.

Original entry on oeis.org

1, -7, -63, -455, -3199, -22407, -156863, -1098055, -7686399, -53804807, -376633663, -2636435655, -18455049599, -129185347207, -904297430463, -6330082013255, -44310574092799, -310174018649607, -2171218130547263, -15198526913830855, -106389688396815999
Offset: 0

Views

Author

Philippe Deléham, Sep 26 2009

Keywords

Programs

  • Mathematica
    (7-4*7^Range[0,20])/3 (* or *) LinearRecurrence[{8,-7},{1,-7},30] (* Harvey P. Dale, Dec 21 2014 *)

Formula

a(n) = 7*a(n-1)-14, a(0)=1.
a(n) = 8*a(n-1) - 7*a(n-2), a(0)= 1, a(1)= -7, for n>1.
G.f.: (1-15x)/(1-8x+7x^2).
a(n) = Sum_{0<=k<=n} A112555(n,k)*(-8)^(n-k).
E.g.f.: (1/3)*(7*exp(x) - 4*exp(7*x)). - G. C. Greubel, Apr 07 2016

Extensions

Corrected and extended by Harvey P. Dale, Dec 21 2014
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