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.

A272648 a(n) = A002119(n) mod 7.

Original entry on oeis.org

1, 1, 0, 1, 0, 1, 1, 6, 6, 0, 6, 0, 6, 6, 1, 1, 0, 1, 0, 1, 1, 6, 6, 0, 6, 0, 6, 6, 1, 1, 0, 1, 0, 1, 1, 6, 6, 0, 6, 0, 6, 6, 1, 1, 0, 1, 0, 1, 1, 6, 6, 0, 6, 0, 6, 6, 1, 1, 0, 1, 0, 1, 1, 6, 6, 0, 6, 0, 6, 6, 1, 1, 0, 1, 0, 1, 1, 6, 6, 0, 6
Offset: 0

Views

Author

N. J. A. Sloane, May 09 2016

Keywords

Comments

Periodic with period 14.

Crossrefs

Programs

  • GAP
    b:=[1,-1];; for n in [3..95] do b[n]:=-2*(2*n-3)*b[n-1]+b[n-2]; od; a:=List(b,AbsInt) mod 7; # Muniru A Asiru, Sep 20 2018
  • Maple
    f:=proc(n) option remember; if n = 0 then 1 elif n=1 then 1 else f(n-2)+(4*n-2)*f(n-1); fi; end;
    [seq(f(n) mod 7, n=0..120)];
  • Mathematica
    PadRight[{},120,{1,1,0,1,0,1,1,6,6,0,6,0,6,6}] (* Harvey P. Dale, Jun 07 2016 *)
  • PARI
    Vec((1+x+x^3+x^5+x^6)*(1+6*x^7)/((1-x)*(1+x)*(1-x+x^2-x^3+x^4-x^5+x^6)*(1+x+x^2+x^3+x^4+x^5+x^6)) + O(x^50)) \\ Colin Barker, May 10 2016
    

Formula

G.f.: (1+x+x^3+x^5+x^6)*(1+6*x^7) / ((1-x)*(1+x)*(1-x+x^2-x^3+x^4-x^5+x^6)*(1+x+x^2+x^3+x^4+x^5+x^6)). - Colin Barker, May 10 2016
a(n) = (-m^6+18*m^5-122*m^4+384*m^3-549*m^2+270*m+24)*(7-5*(-1)^floor(n/7))/48, where m = (n mod 7). - Luce ETIENNE, Sep 21 2018
Showing 1-1 of 1 results.