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.

Showing 1-4 of 4 results.

A155980 First differences of A135351.

Original entry on oeis.org

0, 2, -2, 3, -1, 5, 3, 13, 19, 45, 83, 173, 339, 685, 1363, 2733, 5459, 10925, 21843, 43693, 87379, 174765, 349523, 699053, 1398099, 2796205, 5592403, 11184813, 22369619, 44739245, 89478483, 178956973, 357913939, 715827885, 1431655763, 2863311533, 5726623059
Offset: 0

Views

Author

Paul Curtz, Feb 01 2009

Keywords

Crossrefs

Cf. A135351.

Programs

  • Mathematica
    LinearRecurrence[{1,2},{0,2,-2,3},50] (* Paolo Xausa, Nov 07 2023 *)

Formula

G.f.: (x^2-4*x+2)*x/((1-2*x)*(x+1)). - Alois P. Heinz, Jan 21 2021

Extensions

More terms from Alois P. Heinz, Jan 21 2021

A163834 a(n) = (4^n + 5)/3.

Original entry on oeis.org

2, 3, 7, 23, 87, 343, 1367, 5463, 21847, 87383, 349527, 1398103, 5592407, 22369623, 89478487, 357913943, 1431655767, 5726623063, 22906492247, 91625968983, 366503875927, 1466015503703, 5864062014807, 23456248059223, 93824992236887, 375299968947543
Offset: 0

Views

Author

Juri-Stepan Gerasimov, Aug 05 2009

Keywords

Crossrefs

Programs

  • Mathematica
    Table[(4^n + 5)/3, {n, 0, 50}] (* G. C. Greubel, Aug 05 2017 *)
    LinearRecurrence[{5,-4},{2,3},30] (* Harvey P. Dale, Jun 14 2023 *)
  • PARI
    x='x+O('x^50); concat([0], Vec((2-7*x)/((4*x-1)*(x-1)))) \\ G. C. Greubel, Aug 05 2017

Formula

a(n) = (4^n + 5)/3 = A135351(2*n+1) = A140966(2*n) = A153643(2*n).
a(n) = 5*a(n-1) - 4*a(n-2).
G.f.: (2-7*x)/((4*x-1)*(x-1)).
a(n+1) - a(n) = A000302(n).
E.g.f.: (1/3)*(5*exp(x) + exp(4*x)). - G. C. Greubel, Aug 05 2017

Extensions

Offset set to 0 by R. J. Mathar, Aug 06 2009

A099754 a(n) = (3^n +1)/2 + 2^n.

Original entry on oeis.org

2, 4, 9, 22, 57, 154, 429, 1222, 3537, 10354, 30549, 90622, 269817, 805354, 2407869, 7207222, 21588897, 64701154, 193972389, 581655022, 1744440777, 5232273754, 15694724109, 47079978022, 141231545457, 423677859154, 1271000023029
Offset: 0

Views

Author

Miklos Kristof, Nov 11 2004

Keywords

Comments

Let b(0)=1, b(n) = A005578(n-1) = {1,1,2,3,6,11,22,43,86,171,342, ...} then a(n) = Sum_{k=0..n+1} C(n+1,k)*b(k).
Binomial transform of A135351. - R. J. Mathar, Aug 05 2009

Examples

			a(6) = (3^6+1)/2 + 2^6 = 365+64 = 429.
a(6) = 1 + 7*1 + 21*1 + 35*2 + 35*3 + 21*6 + 7*11 + 1*22 = 429.
		

Crossrefs

Cf. A005578.

Programs

  • GAP
    List([0..30], n-> (3^n +2^(n+1) +1)/2); # G. C. Greubel, Sep 03 2019
  • Magma
    [(3^n +2^(n+1) +1)/2: n in [0..30]]; // G. C. Greubel, Sep 03 2019
    
  • Maple
    seq((3^n +2^(n+1) +1)/2, n=0..30); # G. C. Greubel, Sep 03 2019
  • Mathematica
    Table[(3^n +2^(n+1) +1)/2, {n,0,30}] (* G. C. Greubel, Sep 03 2019 *)
    LinearRecurrence[{6,-11,6},{2,4,9},30] (* Harvey P. Dale, May 23 2021 *)
  • PARI
    a(n) = (3^n+1)/2 + 2^n; \\ Michel Marcus, Aug 15 2013
    
  • Sage
    [(3^n +2^(n+1) +1)/2 for n in (0..30)] # G. C. Greubel, Sep 03 2019
    

Formula

a(n) = (3^n + 2^(n+1) + 1)/2.
G.f.: (2-8*x+7*x^2)/((1-x)*(1-2*x)*(1-3*x)). - Jaume Oliver Lafont, Mar 06 2009
a(n) = A007051(n) + A000079(n). - Michel Marcus, Aug 15 2013
E.g.f.: (exp(x) + 2*exp(2*x) + exp(3*x))/2. - G. C. Greubel, Sep 03 2019

Extensions

Corrected and extended by T. D. Noe, Nov 07 2006

A171382 a(n) = (2*2^n+7*(-1)^n)/3.

Original entry on oeis.org

3, -1, 5, 3, 13, 19, 45, 83, 173, 339, 685, 1363, 2733, 5459, 10925, 21843, 43693, 87379, 174765, 349523, 699053, 1398099, 2796205, 5592403, 11184813, 22369619, 44739245, 89478483, 178956973, 357913939, 715827885, 1431655763, 2863311533
Offset: 0

Views

Author

Klaus Brockhaus, Dec 07 2009

Keywords

Comments

a(n) = A155980(n+2).
a(n) = A135351(n+3)-A135351(n+2).
Second binomial transform of a signed version of A005032 preceded by 3.
Inverse binomial transform of A008776 preceded by 3.

Crossrefs

Cf. A155980 (First differences of A135351), A135351 ((2^n+3-7*(-1)^n+3*0^n)/6), A005032 (7*3^n), A008776 (2*3^n).

Programs

  • Magma
    [ (2*2^n+7*(-1)^n)/3: n in [0..32] ];
  • Mathematica
    Nest[Append[#,Last[#]+2#[[-2]]]&,{3,-1},40]  (* Harvey P. Dale, Apr 07 2011 *)

Formula

a(n) = a(n-1)+2*a(n-2) for n > 1; a(0) = 3, a(1) = -1.
a(n) = 2^n-a(n-1) for n > 0; a(0) = 3.
G.f.: (3-4*x)/((1+x)*(1-2*x)).
Showing 1-4 of 4 results.