OFFSET
0,2
LINKS
Robert Price, Table of n, a(n) for n = 0..1000
Eric Weisstein's World of Mathematics, Elementary Cellular Automaton
Stephen Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 55.
Index entries for linear recurrences with constant coefficients, signature (0,10001,0,-10000).
FORMULA
From Colin Barker, Jan 17 2016 and Apr 17 2019: (Start)
a(n) = 10001*a(n-2) - 10000*a(n-4) for n>3.
G.f.: (1+101*x+1000*x^3) / ((1-x)*(1+x)*(1-100*x)*(1+100*x)).
(End)
a(n) = floor((10000 + 110*(n mod 2))*100^n/9999). - Karl V. Keller, Jr., Aug 11 2021
MATHEMATICA
rule=147; 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([(10000 + 110*(n%2))*100**n//9999 for n in range(30)]) # Karl V. Keller, Jr., Aug 11 2021
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Robert Price, Jan 17 2016
STATUS
approved