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A122803 Powers of -2. 11
1, -2, 4, -8, 16, -32, 64, -128, 256, -512, 1024, -2048, 4096, -8192, 16384, -32768, 65536, -131072, 262144, -524288, 1048576, -2097152, 4194304, -8388608, 16777216, -33554432, 67108864, -134217728, 268435456, -536870912, 1073741824, -2147483648, 4294967296 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

Sum_{n>=0} 1/a(n) = 2/3 [From Jaume Oliver Lafont (joliverlafont(AT)gmail.com), Mar 01 2009]

LINKS

Franklin T. Adams-Watters, Table of n, (-2)^n for n = 0..1000

Index entries for sequences related to linear recurrences with constant coefficients

Tanya Khovanova, Recursive Sequences

FORMULA

a(n) = (-2)^n.

a(n) = - 4a(n-1) - 4a(n-2). - Tanya Khovanova (tanyakh(AT)yahoo.com), Feb 01 2007

a(n)=-2*a(n-1), n>0 ; a(0)=1 . G.f.: 1/(1+2x). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 19 2008]

MAPLE

a:=n->mul(-2, k=0..n): seq(a(n), n=-1..31); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jan 22 2008

MATHEMATICA

Table[(-2)^n, {n, 0, 50}] (*From Vladimir Joseph Stephan Orlovsky, Feb 15 2011*)

CROSSREFS

Cf. A000079 (powers of 2).

Sequence in context: A141531 A166444 A084633 * A000079 A120617 A131577

Adjacent sequences:  A122800 A122801 A122802 * A122804 A122805 A122806

KEYWORD

easy,sign

AUTHOR

Franklin T. Adams-Watters (FrankTAW(AT)Netscape.net), Sep 11 2006

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Last modified February 4 12:08 EST 2012. Contains 204817 sequences.