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 1-3 of 3 results.

A133599 A097806 * A133080 * A007318.

Original entry on oeis.org

1, 3, 1, 3, 3, 1, 3, 7, 5, 1, 3, 9, 10, 5, 1, 3, 13, 22, 18, 7, 1, 3, 15, 31, 34, 21, 7, 1, 3, 19, 51, 75, 65, 33, 9, 1, 3, 21, 64, 111, 120, 83, 36, 9, 1, 3, 25, 92, 196, 266, 238, 140, 52, 11, 1
Offset: 1

Views

Author

Gary W. Adamson, Sep 18 2007

Keywords

Comments

Row sums = A133600: (1, 4, 7, 16, 28, 64, 112, ...).

Examples

			First few rows of the triangle:
  1;
  3,  1;
  3,  3,  1;
  3,  7,  5,  1;
  3,  9, 10,  5,  1;
  3, 13, 22, 18,  7,  1;
  ...
		

Crossrefs

Programs

Formula

A097806 * A133080 * A007318 as infinite lower triangular matrices, where A097806 = the pairwise operator and A133080 = an interpolation operator.

A137480 a(n)=4a(n-2).

Original entry on oeis.org

12, 21, 48, 84, 192, 336, 768, 1344, 3072, 5376, 12288, 21504, 49152, 86016, 196608, 344064, 786432, 1376256, 3145728, 5505024, 12582912, 22020096, 50331648, 88080384, 201326592, 352321536, 805306368, 1409286144, 3221225472, 5637144576, 12884901888
Offset: 0

Views

Author

Paul Curtz, Apr 22 2008

Keywords

Programs

  • Mathematica
    LinearRecurrence[{0, 4}, {12, 21}, 50] (* G. C. Greubel, Feb 23 2017 *)
  • PARI
    x='x + O('x^50); Vec((21*x + 12)/(-4*x^2 + 1)) \\ G. C. Greubel, Feb 23 2017

Formula

G.f.: (21*x + 12)/(-4*x^2 + 1).
a(n) = -(9/4)*sqrt(2)*(1/2)^(-1/2*(-1)^n)*(-2)^n + (33/4)*2^n*sqrt(2)*(1/2)^(-(1/2)*(-1)^n) - Alexander R. Povolotsky, Apr 25 2008
a(n) = 3*A133600(n+2) - R. J. Mathar, Jun 08 2016

A171475 a(n) = 6*a(n-1) - 8*a(n-2), for n > 2, with a(0) = 1, a(1) = 6, a(2) = 27.

Original entry on oeis.org

1, 6, 27, 114, 468, 1896, 7632, 30624, 122688, 491136, 1965312, 7862784, 31454208, 125822976, 503304192, 2013241344, 8053014528, 32212156416, 128848822272, 515395682304, 2061583515648, 8246335635456, 32985345687552
Offset: 0

Views

Author

Klaus Brockhaus, Dec 09 2009

Keywords

Comments

Binomial transform of A037480; second binomial transform of A133600.
First differences of A080960.

Crossrefs

Cf. A037480 ((5*3^n +(-1)^n -6)/8), A133600 (row sums of triangle A133599), A080960 (third binomial transform of A010685).

Programs

  • Magma
    I:=[6,27]; [1] cat [n le 2 select I[n] else 6*Self(n-1) - 8*Self(n-2): n in [1..30]]; // G. C. Greubel, Dec 02 2021
    
  • Mathematica
    Table[If[n==0, 1, 3*(5*4^n - 2*2^n)/8],{n,0,30}] (* G. C. Greubel, Dec 02 2021 *)
    LinearRecurrence[{6,-8},{1,6,27},30] (* Harvey P. Dale, Oct 25 2023 *)
  • PARI
    {m=21; v=concat([1, 6, 27], vector(m-3)); for(n=4, m, v[n]=6*v[n-1]-8*v[n-2]); v}
    
  • Sage
    [1]+[3*(5*4^n - 2*2^n)/8 for n in (1..30)] # G. C. Greubel, Dec 02 2021

Formula

a(n) = 3*(5*4^n - 2*2^n)/8 for n > 0.
G.f.: (1-x)*(1+x)/((1-2*x)*(1-4*x)).
E.g.f.: (1/8)*(-1 - 6*exp(2*x) + 15*exp(4*x)). - G. C. Greubel, Dec 02 2021
Showing 1-3 of 3 results.