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A135583
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a(n) = 4a(n-1)-4.
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1
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3, 8, 28, 108, 428, 1708, 6828, 27308, 109228, 436908, 1747628, 6990508, 27962028, 111848108, 447392428, 1789569708, 7158278828, 28633115308, 114532461228, 458129844908, 1832519379628, 7330077518508, 29320310074028
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 0..1000
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FORMULA
| a(n) = (4+5*4^n)/3 . a(n)-a(n-1) = A003947(n). O.g.f.: -(-3+7*x)/[(-1+x)(-1+4*x)]. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Mar 31 2008
a(n)=-(4/3)+(13/3)*4^n, for n>=0 - Paolo P. Lava (paoloplava(AT)gmail.com), Jun 06 2008
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PROG
| (MAGMA) [(4+5*4^n)/3: n in [0..30]]; // Vincenzo Librandi, Aug 10 2011
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CROSSREFS
| Sequence in context: A148866 A151431 A093356 * A009437 A000776 A000239
Adjacent sequences: A135580 A135581 A135582 * A135584 A135585 A135586
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KEYWORD
| nonn,easy
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AUTHOR
| Paul Curtz (bpcrtz(AT)free.fr), Feb 25 2008
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EXTENSIONS
| More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Mar 31 2008
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