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.

A123166 Row sums of A123162.

Original entry on oeis.org

1, 2, 5, 17, 65, 257, 1025, 4097, 16385, 65537, 262145, 1048577, 4194305, 16777217, 67108865, 268435457, 1073741825, 4294967297, 17179869185, 68719476737, 274877906945, 1099511627777, 4398046511105, 17592186044417, 70368744177665, 281474976710657, 1125899906842625, 4503599627370497, 18014398509481985
Offset: 0

Views

Author

Roger L. Bagula, Oct 02 2006

Keywords

Crossrefs

Programs

  • Magma
    [0] cat [4^(n-1) +1: n in [1..40]]; // G. C. Greubel, May 31 2022
    
  • Maple
    a[0]:=0:a[1]:=1:for n from 2 to 50 do a[n]:=4*a[n-1] od: seq(a[n]+sum((k), k=0..1), n=0..20); # Zerinvary Lajos, Mar 20 2008
  • Mathematica
    A123162[n_, k_]= If [k==0, 1, Binomial[2*n-1, 2*k-1]];
    Table[Sum[A123162[n, k], {k,0,n}], {n,0,30}]
    Table[4^(n-1) +1 -Boole[n==0]/4, {n,0,40}] (* G. C. Greubel, May 31 2022 *)
  • SageMath
    [4^(n-1) +1 -bool(n==0)/4 for n in (0..40)] # G. C. Greubel, May 31 2022

Formula

a(n) = 1 + Sum_{k=0..n} binomial(2*n-1, 2*k-1), for n > 0. - Paul Barry, May 26 2008
a(n) = A052539(n-1), n > 0. - R. J. Mathar, Jun 18 2008
From Sergei N. Gladkovskii, Dec 20 2011: (Start)
G.f.: (1 - 3*x - x^2)/((1-x)*(1-4*x)).
E.g.f.: (exp(4*x) + 4*exp(x) - 1)/4 = (G(0) - 1)/4; G(k) = 1 + 4/(4^k-x*16^k/(x*4^k+(k+1)/G(k+1))); (continued fraction). (End)

Extensions

Edited by N. J. A. Sloane, Oct 04 2006