The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A266435 Binary representation of the n-th iteration of the "Rule 23" elementary cellular automaton starting with a single ON (black) cell. 3
 1, 111, 0, 1111111, 0, 11111111111, 0, 111111111111111, 0, 1111111111111111111, 0, 11111111111111111111111, 0, 111111111111111111111111111, 0, 1111111111111111111111111111111, 0, 11111111111111111111111111111111111, 0, 111111111111111111111111111111111111111 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Rules 31, 55, 63, 87, 95, 119 and 127 also generate this sequence. REFERENCES S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 55. LINKS Robert Price, Table of n, a(n) for n = 0..500 Eric Weisstein's World of Mathematics, Elementary Cellular Automaton S. Wolfram, A New Kind of Science Index entries for sequences related to cellular automata Index to Elementary Cellular Automata FORMULA From Colin Barker, Dec 30 2015 and Apr 15 2019: (Start) a(n) = ((-1)^n-1)*(1-10^(2*n+1))/18 for n>0. a(n) = 10001*a(n-2)-10000*a(n-4) for n>4. G.f.: (1+111*x-10001*x^2+1000*x^3+10000*x^4) / ((1-x)*(1+x)*(1-100*x)*(1+100*x)). (End) a(n) = (10*100^n-1)/9*(n mod 2) + 0^n. - Karl V. Keller, Jr., Aug 11 2021 MATHEMATICA rule=23; rows=20; ca=CellularAutomaton[rule, {{1}, 0}, rows-1, {All, All}]; (* Start with single black cell *) catri=Table[Take[ca[[k]], {rows-k+1, rows+k-1}], {k, 1, rows}]; (* Truncated list of each row *) Table[FromDigits[catri[[k]]], {k, 1, rows}] (* Binary Representation of Rows *) PROG (Python) print([(10*100**n-1)//9*(n%2) + 0**n for n in range(33)]) # Karl V. Keller, Jr., Aug 11 2021 CROSSREFS Cf. A266434, A266436. Sequence in context: A280141 A280142 A077573 * A216479 A123698 A123727 Adjacent sequences: A266432 A266433 A266434 * A266436 A266437 A266438 KEYWORD nonn,easy AUTHOR Robert Price, Dec 29 2015 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified June 10 17:16 EDT 2023. Contains 363206 sequences. (Running on oeis4.)