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 1-7 of 7 results.

A071048 Number of 0's in n-th row of triangle in A070887.

Original entry on oeis.org

0, 0, 0, 1, 0, 3, 2, 2, 1, 5, 5, 4, 5, 6, 4, 5, 4, 9, 8, 9, 8, 8, 7, 10, 11, 13, 14, 11, 7, 10, 15, 15, 9, 15, 21, 17, 12, 20, 19, 15, 17, 23, 19, 13, 18, 20, 23, 26, 17, 19, 23, 28, 24, 20, 25, 25, 20, 24, 25, 24, 26, 28, 28, 28, 22, 26, 31, 30, 32, 31, 31, 28, 29, 32
Offset: 0

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Author

Hans Havermann, May 26 2002

Keywords

References

  • S. Wolfram, A New Kind of Science, Wolfram Media, 2002; Chapter 3.

A070886 Triangle read by rows giving successive states of cellular automaton generated by "Rule 90".

Original entry on oeis.org

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

Views

Author

N. J. A. Sloane, May 19 2002

Keywords

Comments

If either neighbor is 1 then new state is 1, otherwise new state is 0.
Row n has length 2n+1.
Rules #18, #26, #82, #90, #146, #154, #210, #218 all give rise to this sequence. - Hans Havermann

Examples

			1; 1,0,1; 1,0,0,0,1; 1,0,1,0,1,0,1; ...
		

References

  • S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 25.

Crossrefs

Cf. A070950, A070887. Alternate rows of A047999. Interpreted as binary numbers: A038183. Interpreted as Zeckendorf-expansions: A048757. Drawn as binary trees: A080263.

Programs

  • Mathematica
    rows = 10; ca = CellularAutomaton[90, {{1}, 0}, rows-1]; Flatten[ Table[ca[[k, rows-k+1 ;; rows+k-1]], {k, 1, rows}]] (* Jean-François Alcover, May 24 2012 *)

Extensions

More terms from Hans Havermann, May 26 2002

A006978 Successive states of the Rule 110 cellular automaton defined by 000, 001, 010, 011, ..., 111 -> 0,1,1,1,0,1,1,0 when started with a single ON cell.

Original entry on oeis.org

1, 3, 7, 13, 31, 49, 115, 215, 509, 775, 1805, 3359, 7985, 12659, 29655, 54909, 130759, 197581, 460383, 855793, 2038675, 3227319, 7562237, 14149127, 33304077, 50625055, 118279729, 220060275, 523730647, 830325757, 1942439431, 3595423245, 8571017759, 12951092785
Offset: 1

Views

Author

Keywords

References

  • Marc LeBrun, personal communication.
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Programs

  • Mathematica
    Map[FromDigits[#, 2] &, CellularAutomaton[110, {{1}, 0}, 30]] (* Ben Branman, Dec 28 2010 *)

Formula

a(n) = A117999(n-1)/2^(n-1). - Pontus von Brömssen, Oct 18 2022

Extensions

More terms from Eric W. Weisstein, Apr 11 2006
Definition clarified by N. J. A. Sloane, Oct 18 2022

A071049 Number of 1's in n-th generation of 1-D CA using Rule 110, started with a single 1.

Original entry on oeis.org

1, 2, 3, 3, 5, 3, 5, 6, 8, 5, 6, 8, 8, 8, 11, 11, 13, 9, 11, 11, 13, 14, 16, 14, 14, 13, 13, 17, 22, 20, 16, 17, 24, 19, 14, 19, 25, 18, 20, 25, 24, 19, 24, 31, 27, 26, 24, 22, 32, 31, 28, 24, 29, 34, 30, 31, 37, 34, 34, 36, 35, 34, 35, 36, 43, 40, 36, 38, 37, 39, 40
Offset: 0

Views

Author

Hans Havermann, May 26 2002

Keywords

Comments

Number of 1's in n-th row of triangle in A070887.
Although the initial behavior is chaotic, it is an astonishing fact, pointed out by Wolfram [2002, p. 39], that after about three thousand terms all the irregularities disappear. - N. J. A. Sloane, May 15 2015

References

  • Matthew Cook, A Concrete View of Rule 110 Computation, in "The Complexity of Simple Programs", T. Neary, D. Woods, A. K. Seda, and N. Murphy (Eds.), 2008, pp. 31-55.
  • S. Wolfram, A New Kind of Science, Wolfram Media, 2002; Chapter 3.

Crossrefs

Programs

Formula

For n >= 2854, a(n+469) = -a(n+453) + a(n+256) + a(n+240) + a(n+229) + a(n+213) - a(n+16) - a(n). - N. J. A. Sloane, May 15 2015

Extensions

Added references and links. - N. J. A. Sloane, Aug 09 2014
Changed offset to make consistent with A070952, etc. - N. J. A. Sloane, Aug 15 2014

A075437 Triangle read by rows giving successive iterations of the Rule 110 elementary cellular automaton starting with a single black (1) cell where row n is of length 2n+1.

Original entry on oeis.org

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

Views

Author

Eric W. Weisstein, Sep 15 2002

Keywords

Comments

The right n terms in a(n) are all 0.
T(n,k) = A070887(n+1,k+1), k=0..n. - Reinhard Zumkeller, Jun 26 2013

Examples

			      1;
    1,1,0;
  1,1,1,0,0;
1,1,0,1,0,0,0; ...
		

References

  • S. Wolfram, A New Kind of Science. Champaign, IL: Wolfram Media, p. 31ff, 2002.

Crossrefs

Cf. A070887.

Programs

  • Haskell
    a075437 n k = a075437_tabf !! n !! k
    a075437_row n = a075437_tabf !! n
    a075437_tabf = iterate rule110 [1] where
       rule110 row = f ([0,0] ++ row ++ [0,0]) where
           f [,]          = []
           f (:ws@(0:0:)) = 0 : f ws
           f (1:ws@(1:1:_)) = 0 : f ws
           f (:ws@(:_:_)) = 1 : f ws
    -- Reinhard Zumkeller, Jun 26 2013
  • Mathematica
    A075437list[rowmax_]:=MapIndexed[ArrayPad[#1,#2-rowmax-1]&,CellularAutomaton[110,{{1},0},{rowmax,All}]];A075437list[10] (* Generates 11 rows *) (* Paolo Xausa, Oct 04 2023 *)

A161903 Convert n into a sequence of binary digits, apply one step of the rule 110 cellular automaton, and interpret the results as a binary integer.

Original entry on oeis.org

0, 3, 6, 7, 12, 15, 14, 13, 24, 27, 30, 31, 28, 31, 26, 25, 48, 51, 54, 55, 60, 63, 62, 61, 56, 59, 62, 63, 52, 55, 50, 49, 96, 99, 102, 103, 108, 111, 110, 109, 120, 123, 126, 127, 124, 127, 122, 121, 112, 115, 118, 119, 124, 127, 126, 125, 104, 107, 110, 111, 100, 103, 98, 97, 192, 195, 198, 199, 204, 207, 206, 205, 216, 219, 222, 223, 220, 223, 218, 217, 240, 243, 246, 247, 252, 255, 254, 253, 248, 251, 254, 255, 244, 247, 242, 241, 224, 227, 230, 231, 236
Offset: 0

Views

Author

Ben Branman, Jan 30 2011

Keywords

Comments

a(a(a(...1))) (n times) gives A006978(n)

Examples

			For n=19, the evolution after one step is
0, 1, 0, 0, 1, 1  (n=19)
1, 1, 0, 1, 1, 1  (a(n)=55)
So a(n)=55.
		

Crossrefs

Programs

  • Mathematica
    a[n_] :=
    FromDigits[
      Drop[Part[CellularAutomaton[110, {IntegerDigits[n, 2], 0}], 1], -1],
       2];Table[a[n],{n,0,100}]

Formula

a(n) = A057889(A269174(A057889(n))). - Antti Karttunen, Jun 02 2018

A237119 Number of white areas in the graph of elementary cellular automaton with rule 110 at generation n.

Original entry on oeis.org

0, 1, 1, 2, 2, 3, 3, 4, 5, 6, 7, 8, 9, 10, 11, 14, 15, 17, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 39, 43, 46, 50, 52, 55, 57, 59, 62, 65, 68, 71, 74, 78, 81, 85, 90, 95, 98
Offset: 0

Views

Author

Philippe Beaudoin, Feb 03 2014

Keywords

Crossrefs

Cf. A070887 (rule 110), A237118 (for rule 30), A237120 (for rule 150).
Showing 1-7 of 7 results.