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 1-2 of 2 results.

A083595 a(n) = (7*2^n - 4(-1)^n)/3.

Original entry on oeis.org

1, 6, 8, 20, 36, 76, 148, 300, 596, 1196, 2388, 4780, 9556, 19116, 38228, 76460, 152916, 305836, 611668, 1223340, 2446676, 4893356, 9786708, 19573420, 39146836, 78293676, 156587348, 313174700, 626349396, 1252698796, 2505397588
Offset: 0

Views

Author

Paul Barry, May 02 2003

Keywords

Comments

Binomial transform of A083594.

Crossrefs

Cf. A082541.

Programs

  • Magma
    [(7*2^n-4*(-1)^n)/3: n in [0..40]]; // Vincenzo Librandi, Apr 28 2011
  • Mathematica
    LinearRecurrence[{1,2},{1,6},40] (* Harvey P. Dale, Aug 13 2019 *)

Formula

a(n) = (7*2^n - 4(-1)^n)/3 .
G.f.: (1+5*x)/((1-2*x)*(1+x)).
E.g.f.: (7*exp(2*x) - 4*exp(-x))/3.

A321358 a(n) = (2*4^n + 7)/3.

Original entry on oeis.org

3, 5, 13, 45, 173, 685, 2733, 10925, 43693, 174765, 699053, 2796205, 11184813, 44739245, 178956973, 715827885, 2863311533, 11453246125, 45812984493, 183251937965, 733007751853, 2932031007405, 11728124029613, 46912496118445, 187649984473773, 750599937895085, 3002399751580333
Offset: 0

Views

Author

Paul Curtz, Nov 07 2018

Keywords

Comments

Difference table:
3, 5, 13, 45, 173, 685, 2733, ... (this sequence)
2, 8, 32, 128, 512, 2048, 8192, ... A004171
6, 24, 96, 384, 1536, 6144, 24576, ... A002023

Crossrefs

Programs

  • Mathematica
    a[n_]:= (2*4^n + 7)/3; Array[a, 20, 0] (* or *)
    CoefficientList[Series[1/3 (7 E^x + 2 E^(4 x)), {x, 0, 20}], x]*Table[n!, {n, 0, 20}] (* Stefano Spezia, Nov 10 2018 *)
  • PARI
    a(n) = (2*4^n + 7)/3; \\ Michel Marcus, Nov 08 2018
    
  • PARI
    Vec((3 - 10*x) / ((1 - x)*(1 - 4*x)) + O(x^30)) \\ Colin Barker, Nov 10 2018

Formula

O.g.f.: (3 - 10*x) / ((1 - x)*(1 - 4*x)). - Colin Barker, Nov 10 2018
E.g.f.: (1/3)*(7*exp(x) + 2*exp(4*x)). - Stefano Spezia, Nov 10 2018
a(n) = 5*a(n-1) - 4*a(n-2), a(0) = 3, a(1) = 5.
a(n) = 4*a(n-1) - 7, a(0) = 3.
a(n) = (2/3)*(4^n-1)/3 + 3.
a(n) = A171382(2*n) = A155980(2*n+2).
a(n) = A193579(n)/3.
a(n) = A007583(n) + 2 = A001045(2*n+1) + 2.

Extensions

More terms from Michel Marcus, Nov 08 2018
Showing 1-2 of 2 results.