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A152166 a(2*n) = 2^n; a(2*n+1) = -(2^(n+1)). 5
1, -2, 2, -4, 4, -8, 8, -16, 16, -32, 32, -64, 64, -128, 128, -256, 256, -512, 512, -1024, 1024, -2048, 2048, -4096, 4096, -8192, 8192, -16384, 16384, -32768, 32768, -65536, 65536, -131072, 131072, -262144, 262144, -524288, 524288, -1048576, 1048576 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Ratios of successive terms are -2,-1,-2,-1,-2,-1,-2,-1,... - Philippe Deléham, Dec 12 2008

LINKS

Table of n, a(n) for n=0..40.

FORMULA

G.f.: (1-2*x)/(1-2*x^2).

a(n) = 2*a(n-2); a(0)=1, a(1)=-2.

a(n) = Sum{k=0..n} A147703(n,k)*(-3)^k.

a(n) = (3/4)*8^(1/4)*(-1)^n*2^((1/2)*n]*2^((1/4)*(-1)^n) - (1/4)*8^(1/4)*2^((1/2)*n)*2^((1/4)*(-1)^n), with n >= 0. - Paolo P. Lava, Dec 01 2008

CROSSREFS

Cf. A000079, A016116.

Sequence in context: A158780 A117575 A131572 * A320770 A016116 A060546

Adjacent sequences:  A152163 A152164 A152165 * A152167 A152168 A152169

KEYWORD

sign

AUTHOR

Philippe Deléham, Nov 27 2008

STATUS

approved

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Last modified April 20 03:02 EDT 2021. Contains 343121 sequences. (Running on oeis4.)