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 1-1 of 1 results.

A092896 Related to random walks on the 4-cube.

Original entry on oeis.org

1, 1, 5, 17, 65, 257, 1025, 4097, 16385, 65537, 262145, 1048577, 4194305, 16777217, 67108865, 268435457, 1073741825, 4294967297, 17179869185, 68719476737, 274877906945, 1099511627777, 4398046511105, 17592186044417, 70368744177665, 281474976710657
Offset: 0

Views

Author

Paul Barry, Mar 12 2004

Keywords

Comments

Gives the denominators in the probability that a random walk on the 4-cube returns to its starting corner on the 2n-th step. Partial sums of A092898. Binomial transform of A092897.
Palindromic numbers in base 2 with an odd number of bits that can be written as 2^(2n) + 1, n >= 1. Palindromic numbers in base 2 with an even number of bits that can be written as 2^(2n+1) + 1 are A087289. - Brad Clardy, Feb 18 2014

Crossrefs

Programs

  • Magma
    [n lt 2 select 1 else 4^(n-1) +1: n in [0..30]]; // G. C. Greubel, Feb 21 2021
  • Maple
    A092896:= n -> `if`(n<2, 1, 4^(n-1) +1); seq(A092896(n), n = 0..30); # G. C. Greubel, Feb 21 2021
  • Mathematica
    CoefficientList[Series[(1 -4x +4x^2 -4x^3)/((1-x)(1-4x)), {x, 0, 40}], x] (* Vincenzo Librandi, Feb 20 2014 *)
    LinearRecurrence[{5,-4}, {1,1,5,17}, 30] (* Harvey P. Dale, Mar 19 2016 *)
  • PARI
    Vec((1-4*x+4*x^2-4*x^3)/((1-x)*(1-4*x)) + O(x^30)) \\ Colin Barker, Nov 25 2016
    
  • Sage
    [1 if n<2 else 4^(n-1) +1 for n in [0..30]]; # G. C. Greubel, Feb 21 2021
    

Formula

G.f.: (1 - 4*x + 4*x^2 - 4*x^3)/((1-x)*(1-4*x)).
a(n) = 1 + 4^n/4 - 0^n/4 + Sum_{k=0..n} binomial(n, k)*k*(-1)^k.
a(n+1) = 4^n + 1 - 0^n = A002450(n+1) - 4*A002450(n-1). - Paul Barry, Mar 13 2008
a(n) = A052539(n-1), n > 1. - R. J. Mathar, Sep 08 2008
Dropping a(0) and interleaving the terms with zeros gives a sequence with e.g.f. (sin(5ix/2)/sin(ix/2) - 3)/2 = cos(2ix) + cos(ix) - 1. Similar expressions apply to A091775 and A074515, which are also power sums representable by the Bernoulli polynomials. - Tom Copeland, Oct 22 2008
a(n) = 4^(n-1) + 1 for n > 1. - Colin Barker, Nov 25 2016
E.g.f.: (exp(4*x) + 4*exp(x) - 1 - 4*x)/4. - G. C. Greubel, Feb 21 2021
Showing 1-1 of 1 results.