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A152239
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a(n)=-5*a(n-1)+7*a(n-2), n>1 ; a(0)=1, a(1)=-7 .
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3
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1, -7, 42, -259, 1589, -9758, 59913, -367871, 2258746, -13868827, 85155357, -522858574, 3210380369, -19711911863, 121032221898, -743144492531, 4562948015941, -28016751527422, 172024393748697, -1056239229435439
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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LINKS
| Index to sequences with linear recurrences with constant coefficients, signature (-5,7).
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FORMULA
| G.f.: (1-2*x)/(1+5*x-7*x^2). a(n)=Sum_{k, 0<=k<=n}A147703(n,k)*(-8)^k.
a(n)=(1/2)*{[ -(5/2)+(1/2)*sqrt(53)]^n+[ -(5/2)-(1/2)*sqrt(53)]^n}+(9/106)*sqrt(53)*{[ -(5/2)-(1/2)*sqrt(53)]^n -[ -(5/2)+(1/2)*sqrt(53)]^n}, with n>=0 [From Paolo P. Lava (paoloplava(AT)gmail.com), Dec 12 2008]
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PROG
| (PARI) Vec((1-2*x)/(1+5*x-7*x^2)+O(x^99)) \\ Charles R Greathouse IV, Jan 17 2012
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CROSSREFS
| Sequence in context: A033133 A082035 A127016 * A152240 A187246 A073506
Adjacent sequences: A152236 A152237 A152238 * A152240 A152241 A152242
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KEYWORD
| sign,easy,less
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AUTHOR
| Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 30 2008
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EXTENSIONS
| Several terms corrected by Johannes W. Meijer (meijgia(AT)hotmail.com), Aug 17 2010
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