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A166956 2^n-2+(-1)^n. 3
0, -1, 3, 5, 15, 29, 63, 125, 255, 509, 1023, 2045, 4095, 8189, 16383, 32765, 65535, 131069, 262143, 524285, 1048575, 2097149, 4194303, 8388605, 16777215, 33554429, 67108863, 134217725, 268435455, 536870909, 1073741823, 2147483645, 4294967295, 8589934589 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

COMMENTS

The inverse binomial transform yields 0,-1,5,-7,17,-31,.. a sign alternating variant of A014551.

In a table of a(n) and higher order differences in successive rows, the main diagonal contains

0, 4, 8, 16,... (zero followed by A020707).

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..240

Index to sequences with homogeneous linear recurrences with constant coefficients, signature (2,1,-2)

FORMULA

a(n) = A000079(n) - A010684(n).

a(n) = 2*a(n-1)+a(n-2)-2*a(n-3). G.f.: x*(5*x-1)/((1-x)*(1-2*x)*(1+x)).

PROG

(MAGMA) [2^n-2+(-1)^n: n in [0..40]]; // Vincenzo Librandi, Apr 28 2011

CROSSREFS

Cf. A166920.

Sequence in context: A003536 A118173 A079450 * A048738 A018454 A126087

Adjacent sequences:  A166953 A166954 A166955 * A166957 A166958 A166959

KEYWORD

sign,easy

AUTHOR

Paul Curtz (bpcrtz(AT)free.fr), Oct 25 2009

EXTENSIONS

Edited and extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Mar 02 2010

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Last modified February 17 10:05 EST 2012. Contains 206009 sequences.