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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; text; 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 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, Oct 25 2009 EXTENSIONS Edited and extended by R. J. Mathar, Mar 02 2010 STATUS approved

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