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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A253070 The subsequence A253069(2^n-1).

Original entry on oeis.org

1, 6, 22, 82, 302, 1106, 4066, 14902, 54678, 200578, 735770, 2699182, 9901550, 36323050, 133247570, 488805718, 1793137798, 6577952882, 24130592458, 88520767614, 324729961566, 1191240790586, 4369952806274, 16030753627238, 58807285300086, 215728897446594, 791380812129402, 2903104763095054
Offset: 0

Views

Author

N. J. A. Sloane, Jan 29 2015

Keywords

Comments

A253069 is the Run Length Transform of this sequence.

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;
    f:=1/x+1+x+x/y+y/x+x*y;
    OddCA2(f,10);
  • Mathematica
    LinearRecurrence[{3, 3, -1, -6, 10, -8, 8}, {1, 6, 22, 82, 302, 1106, 4066}, 28] (* Jean-François Alcover, Nov 27 2017 *)
  • PARI
    Vec(-(2*x+1)*(2*x^5+x^3-x^2+x+1)/(8*x^7-8*x^6+10*x^5-6*x^4-x^3+3*x^2+3*x-1) + O(x^30)) \\ Colin Barker, Jul 16 2015

Formula

G.f.: (1+2*x)*(1+x-x^2+x^3+2*x^5)/(1-3*x-3*x^2+x^3+6*x^4-10*x^5+8*x^6-8*x^7). - Doron Zeilberger, Feb 18 2015

Extensions

a(11) and a(12) (Maple on a 32 GB machine) from R. J. Mathar, Feb 04 2015
a(13) onwards from Doron Zeilberger, Feb 18 2015 (the terms previously listed were wrong). - N. J. A. Sloane, Feb 19 2015
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