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 A091103 Expansion of (1-3x+12x^2)/((1-3x)(1+3x)). 0
 1, -3, 21, -27, 189, -243, 1701, -2187, 15309, -19683, 137781, -177147, 1240029, -1594323, 11160261, -14348907, 100442349, -129140163, 903981141, -1162261467, 8135830269, -10460353203, 73222472421, -94143178827, 659002251789, -847288609443 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS a(0)=1, a(2n-1)=-k^(2n-1), a(2n)=(3k-2)k^(2n-1), k=3; G.f.: (1-kx+2(k-1)kx^2)/((1-kx)(1+kx)), k=3. LINKS Index entries for linear recurrences with constant coefficients, signature (0,9). FORMULA a(n)=2*3^n/3+5(-3)^n/3-4*0^n/3 CROSSREFS Sequence in context: A050586 A074217 A062219 * A292310 A045802 A006133 Adjacent sequences:  A091100 A091101 A091102 * A091104 A091105 A091106 KEYWORD easy,sign AUTHOR Paul Barry, Dec 22 2003 STATUS approved

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Last modified August 4 13:53 EDT 2021. Contains 346447 sequences. (Running on oeis4.)