|
|
A059153
|
|
a(n) = 2^(n+2)*(2^(n+1)-1).
|
|
8
|
|
|
4, 24, 112, 480, 1984, 8064, 32512, 130560, 523264, 2095104, 8384512, 33546240, 134201344, 536838144, 2147418112, 8589803520, 34359476224, 137438429184, 549754765312, 2199021158400, 8796088827904, 35184363700224, 140737471578112, 562949919866880
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,1
|
|
COMMENTS
|
A hierarchical sequence (S(W'2{2}c) - see A059126).
a(n) written in base 2: 100, 11000, 1110000, ..., i.e., (n+1) times 1 and (n+2) times 0 (see A163663). - Jaroslav Krizek, Aug 12 2009
Also, the number of active (ON,black) cells at stage 2^n-1 of the two-dimensional cellular automaton defined by "Rule 513", based on the 5-celled von Neumann neighborhood.
|
|
REFERENCES
|
S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 170.
|
|
LINKS
|
|
|
FORMULA
|
a(n) = 6*a(n-1) - 8*a(n-2).
G.f.: 4 / ((2*x-1)*(4*x-1)). (End)
|
|
MATHEMATICA
|
|
|
PROG
|
(PARI) { for (n = 0, 200, write("b059153.txt", n, " ", 2^(n + 2)*(2^(n + 1) - 1)); ) } \\ Harry J. Smith, Jun 25 2009
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|