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 A266259 Total number of OFF (white) cells after n iterations of the "Rule 11" elementary cellular automaton starting with a single ON (black) cell. 2
 0, 2, 5, 7, 14, 16, 27, 29, 44, 46, 65, 67, 90, 92, 119, 121, 152, 154, 189, 191, 230, 232, 275, 277, 324, 326, 377, 379, 434, 436, 495, 497, 560, 562, 629, 631, 702, 704, 779, 781, 860, 862, 945, 947, 1034, 1036, 1127, 1129, 1224, 1226, 1325, 1327, 1430 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 REFERENCES S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 55. LINKS Robert Price, Table of n, a(n) for n = 0..999 Eric Weisstein's World of Mathematics, Elementary Cellular Automaton FORMULA Conjectures from Colin Barker, Dec 27 2015 and Apr 14 2019: (Start) a(n) = ((n+1)^2+(-1)^n*(n-1))/2. a(n) = a(n-1)+2*a(n-2)-2*a(n-3)-a(n-4)+a(n-5) for n>4. G.f.: x*(2+3*x-2*x^2+x^3) / ((1-x)^3*(1+x)^2). (End) MATHEMATICA rule=11; 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 *) nbc=Table[Total[catri[[k]]], {k, 1, rows}]; (* Number of Black cells in stage n *) nwc=Table[Length[catri[[k]]]-nbc[[k]], {k, 1, rows}]; (* Number of White cells in stage n *) Table[Total[Take[nwc, k]], {k, 1, rows}] (* Number of White cells through stage n *) CROSSREFS Cf. A266253. Sequence in context: A230301 A031457 A044990 * A133146 A217753 A022771 Adjacent sequences:  A266256 A266257 A266258 * A266260 A266261 A266262 KEYWORD nonn,easy AUTHOR Robert Price, Dec 25 2015 EXTENSIONS Conjectures from Colin Barker, Apr 14 2019 STATUS approved

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Last modified February 23 14:27 EST 2020. Contains 332161 sequences. (Running on oeis4.)