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 1-5 of 5 results.

A104106 a(1) = 1; thereafter, if A(k) = sequence of first 2^k -1 terms, then A(k+1) = A(k),1,A(k) if a(k) = 0, and A(k+1) = A(k),0,A(k) if a(k) = 1.

Original entry on oeis.org

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

Views

Author

Leroy Quet, Mar 04 2005

Keywords

Crossrefs

Programs

  • Maple
    a:= Vector(2^9-1):
    a[1]:= 1;
    for k from 1 to 8 do
      a[2^k]:= 1-a[k];
      a[2^k+1..2^(k+1)-1]:= a[1..2^k-1]
    od:
    convert(a,list); # Robert Israel, May 07 2018
  • Mathematica
    f[l_]:=Join[l,1-{l[[Log[2,Length[l]+1]]]},l];Nest[f,{1},7] (* Ray Chandler, Apr 05 2009 *)

Formula

a(n) = A089242(n) mod 2. - Christian Krause, Mar 19 2021

Extensions

Edited and extended by Ray Chandler, Apr 05 2009

A104105 a(1) = 1, if A(k) = sequence of first 2^k -1 terms and if B(k) is A(k) with 0's and 1's exchanged, then A(k+1) = A(k),1,B(k) if a(k) = 0, A(k+1) = A(k),0,B(k) if a(k) = 1.

Original entry on oeis.org

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

Views

Author

Leroy Quet, Mar 04 2005

Keywords

Crossrefs

Programs

  • Mathematica
    f[l_]:=Join[l,1-{l[[Log[2,Length[l]+1]]]},1-l];Nest[f,{1},7] (* Ray Chandler, Apr 05 2009 *)

Extensions

Edited and extended by Ray Chandler, Apr 05 2009

A104107 a(1) = 1, c(1)=1, if A(k) = sequence of first c(k) terms and if B(k) is A(k) with 0's and 1's exchanged, then A(k+1) = A(k)B(k) and c(k+1)= 2*c(k) if a(k) = 0, A(k+1) = A(k),0,B(k) and c(k+1)= 2*c(k)+1 if a(k) = 1.

Original entry on oeis.org

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

Views

Author

Leroy Quet, Mar 04 2005

Keywords

Crossrefs

Programs

  • Mathematica
    f[l_]:=Join[l,If[l[[Floor[Log[2,Length[l]]]+1]]==0,{},{0}],1-l];Nest[f,{1},7] (* Ray Chandler, Apr 05 2009 *)

Extensions

Edited and extended by Ray Chandler, Apr 05 2009

A104108 a(1) = 1, c(1)=1, if A(k) = sequence of first c(k) terms and if B(k) is A(k) with 0's and 1's exchanged, then A(k+1) = A(k)B(k) and c(k+1)= 2*c(k) if a(k) = 1, A(k+1) = A(k),0,B(k) and c(k+1)= 2*c(k)+1 if a(k) = 0.

Original entry on oeis.org

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

Views

Author

Leroy Quet, Mar 04 2005

Keywords

Crossrefs

Programs

  • Mathematica
    f[l_]:=Join[l,If[l[[Floor[Log[2,Length[l]]]+1]]==1,{},{0}],1-l];Nest[f,{1},7] (* Ray Chandler, Apr 05 2009 *)

Extensions

Edited and extended by Ray Chandler, Apr 05 2009

A112539 Half-baked Thue-Morse: at successive steps the sequence or its bit-inverted form is appended to itself.

Original entry on oeis.org

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

Views

Author

Alexandre Losev, Dec 15 2005

Keywords

Examples

			Triangle begins:
  1;
  0;
  1, 0;
  0, 1, 0, 1;
  1, 0, 1, 0, 0, 1, 0, 1;
  0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0;
  1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0;
  ...
		

Crossrefs

Cf. A112865 (as +-1), A341389 (complement).

Programs

  • Mathematica
    s = {1}; Do[s = Join[s, Mod[s + 1, 2]]; s = Join[s, s], {n, 4}]; s (* Robert G. Wilson v, Dec 22 2005 *)
  • PARI
    aiter(x) = my(s=[1]); for(i=1, x, s=concat(s, if(i%2, [1-e|e<-s], s))); s \\ Ruud H.G. van Tol, Jan 20 2025
  • Python
    s = [1]
    for _ in range(4):
        s = s + [(x + 1) % 2 for x in s]
        s = s + s
    print(s) # Robert C. Lyons, Jan 19 2025
    

Extensions

More terms from Robert G. Wilson v, Dec 22 2005
Showing 1-5 of 5 results.