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.

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.

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%I A075437 #26 Feb 16 2025 08:32:47
%S A075437 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,
%T A075437 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,
%U A075437 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
%N 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.
%C A075437 The right n terms in a(n) are all 0.
%C A075437 T(n,k) = A070887(n+1,k+1), k=0..n. - _Reinhard Zumkeller_, Jun 26 2013
%D A075437 S. Wolfram, A New Kind of Science. Champaign, IL: Wolfram Media, p. 31ff, 2002.
%H A075437 Reinhard Zumkeller, <a href="/A075437/b075437.txt">Rows n = 0..100 of triangle, flattened</a>
%H A075437 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Rule110.html">Rule 110</a>
%H A075437 S. Wolfram, <a href="http://wolframscience.com/">A New Kind of Science</a>
%H A075437 <a href="/index/Ce#cell">Index entries for sequences related to cellular automata</a>
%H A075437 <a href="https://oeis.org/wiki/Index_to_Elementary_Cellular_Automata">Index to Elementary Cellular Automata</a>
%e A075437       1;
%e A075437     1,1,0;
%e A075437   1,1,1,0,0;
%e A075437 1,1,0,1,0,0,0; ...
%t A075437 A075437list[rowmax_]:=MapIndexed[ArrayPad[#1,#2-rowmax-1]&,CellularAutomaton[110,{{1},0},{rowmax,All}]];A075437list[10] (* Generates 11 rows *) (* _Paolo Xausa_, Oct 04 2023 *)
%o A075437 (Haskell)
%o A075437 a075437 n k = a075437_tabf !! n !! k
%o A075437 a075437_row n = a075437_tabf !! n
%o A075437 a075437_tabf = iterate rule110 [1] where
%o A075437    rule110 row = f ([0,0] ++ row ++ [0,0]) where
%o A075437        f [_,_]          = []
%o A075437        f (_:ws@(0:0:_)) = 0 : f ws
%o A075437        f (1:ws@(1:1:_)) = 0 : f ws
%o A075437        f (_:ws@(_:_:_)) = 1 : f ws
%o A075437 -- _Reinhard Zumkeller_, Jun 26 2013
%Y A075437 Cf. A070887.
%K A075437 nonn,tabf
%O A075437 0,1
%A A075437 _Eric W. Weisstein_, Sep 15 2002