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 1-2 of 2 results.

A241685 The total number of squares and rectangles appearing in the Thue-Morse sequence logical matrices after n stages.

Original entry on oeis.org

0, 2, 4, 18, 60, 242, 924, 3698, 14620, 58482, 233244, 932978, 3729180, 14916722, 59655964, 238623858, 954451740, 3817806962, 15271053084, 61084212338, 244336150300, 977344601202, 3909375608604
Offset: 0

Views

Author

Kival Ngaokrajang, Apr 27 2014

Keywords

Comments

a(n) is the total number of unit squares (A241682), 2 X 2 squares (A241683), 2 X 1 and 1 X 2 rectangles (A241684) that appear in the Thue-Morse logical matrices after n stages. See links for more details.

Crossrefs

Cf. A010060.

Programs

  • Mathematica
    Table[Floor[(2^(n + 2) + 3 - (-1)^n)^2/72], {n, 0, 50}] (* G. C. Greubel, Sep 29 2017 *)
  • PARI
    {for (n=1,50, b=(2^(n+1)+3+(-1)^n)/6; a=floor(b^2/2); print1(a,","))}

Formula

a(n) = A007590(A005578(n+1)).
Empirical g.f.: -2*x*(4*x^3-4*x^2-2*x+1) / ((x-1)*(x+1)*(2*x-1)*(2*x+1)*(4*x-1)). - Colin Barker, Apr 27 2014
a(n) = floor((2^(n + 2) + 3 - (-1)^n)^2/72). - G. C. Greubel, Sep 29 2017

A241891 Total number of unit squares appearing in the Thue-Morse sequence of logical matrices (1, 0 version) after n stages.

Original entry on oeis.org

1, 2, 4, 8, 20, 72, 244, 968, 3700, 14792, 58484, 233928, 932980, 3731912, 14916724, 59666888, 238623860, 954495432, 3817806964, 15271227848, 61084212340, 244336849352, 977344601204, 3909378404808, 15637502434420
Offset: 0

Views

Author

Kival Ngaokrajang, May 01 2014

Keywords

Comments

a(n) is the total number of isolated "1s" (no adjacent 1s in the horizontal or vertical directions) which appear as unit squares in the Thue-Morse sequence (another version starts with 1) of logical matrices after n stages. See links for more details.

Crossrefs

Programs

  • PARI
    {a0=1;a1=2;print1(a0,", ",a1,", "); for (n=0,50, b=ceil(2*(2^n-1)/3); a=1-(-1)^b+4*b+2*b^2; if(Mod(n,2)==0, a=a+4); print1(a,", "))}
    
  • PARI
    Vec(-(24*x^5+12*x^4+2*x^3-9*x^2-2*x+1)/((x-1)*(x+1)*(2*x-1)*(2*x+1)*(4*x-1)) + O(x^100)) \\ Colin Barker, Jan 17 2015

Formula

a(n) = A033691(A001045(n)) for n > 2, a(0) = 1, a(1) = 2, a(2) = 4.
a(n) = 4*a(n-1)+5*a(n-2)-20*a(n-3)-4*a(n-4)+16*a(n-5). - Colin Barker, Jan 17 2015
G.f.: -(24*x^5+12*x^4+2*x^3-9*x^2-2*x+1) / ((x-1)*(x+1)*(2*x-1)*(2*x+1)*(4*x-1)). - Colin Barker, Jan 17 2015
Showing 1-2 of 2 results.