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A291778
a(n) = 2^floor(2*n/3).
5
1, 1, 2, 4, 4, 8, 16, 16, 32, 64, 64, 128, 256, 256, 512, 1024, 1024, 2048, 4096, 4096, 8192, 16384, 16384, 32768, 65536, 65536, 131072, 262144, 262144, 524288, 1048576, 1048576, 2097152, 4194304, 4194304, 8388608, 16777216, 16777216, 33554432, 67108864, 67108864
OFFSET
0,3
FORMULA
a(n) = 2^A004523(n).
G.f.: (1+x+2*x^2)/(1-4*x^3). - Robert Israel, Sep 01 2017
From Amiram Eldar, Sep 29 2022: (Start)
Sum_{n>=0} 1/a(n) = 10/3.
Sum_{n>=0} (-1)^n/a(n) = 2/5. (End)
MAPLE
seq(2^floor(2*n/3), n=0..100); # Robert Israel, Sep 01 2017
MATHEMATICA
LinearRecurrence[{0, 0, 4}, {1, 1, 2}, 41] (* Jean-François Alcover, Apr 02 2019 *)
CROSSREFS
Sequence in context: A227594 A321241 A290128 * A089887 A161816 A240347
KEYWORD
nonn
AUTHOR
Don Reble and N. J. A. Sloane, Aug 31 2017
STATUS
approved