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.

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A253072 The subsequence A253071(2^n-1).

Original entry on oeis.org

1, 7, 21, 95, 333, 1319, 4837, 18447, 68733, 259447, 972565, 3661535, 13756333, 51754567, 194586181, 731919279, 2752461533, 10352254743, 38932913525, 146424889471, 550683608589, 2071066796007, 7789015542949, 29293584500047, 110169505843517, 414334209685687
Offset: 0

Views

Author

N. J. A. Sloane, Jan 31 2015

Keywords

Comments

A253071 is the Run Length Transform of this sequence.
A253072(2^k-1) = A050476(2^k-1), 0<=k<=3. This is just a coincidence, since it fails at m=4. - Omar E. Pol, Feb 01 2015; N. J. A. Sloane, Feb 20 2015

Crossrefs

Programs

  • Maple
    OddCA2:=proc(f,M) local n,a,i,f2,g,p;
    f2:=simplify(expand(f)) mod 2;
    p:=1; g:=f2;
    for n from 1 to M do p:=expand(p*g) mod 2; print(n,nops(p)); g:=expand(g^2) mod 2; od:
    return;
    end;
    f25:=1/(x*y)+1/x+1/y+y+x/y+x+x*y;
    OddCA2(f25,8);
  • Mathematica
    LinearRecurrence[{6, -5, -24, 44, -8}, {1, 7, 21, 95, 333}, 26] (* Jean-François Alcover, Nov 27 2017 *)
  • PARI
    Vec(-(8*x^4-28*x^3+16*x^2-x-1)/(8*x^5-44*x^4+24*x^3+5*x^2-6*x+1) + O(x^30)) \\ Colin Barker, Jul 16 2015

Formula

G.f.: -(-1-t+16*t^2-28*t^3+8*t^4)/(1-6*t+5*t^2+24*t^3-44*t^4+8*t^5).
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