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A131885
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a(n) = 4a(n-1)-6a(n-2)+4a(n-3), n > 3; a(0) = 1, a(1) = 2, a(2) = 4, a(3) = 6.
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1, 2, 4, 6, 8, 12, 24, 56, 128, 272, 544, 1056, 2048, 4032, 8064, 16256, 32768, 65792, 131584, 262656, 524288, 1047552, 2095104, 4192256, 8388608, 16781312, 33562624, 67117056, 134217728, 268419072, 536838144, 1073709056, 2147483648, 4295032832, 8590065664
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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FORMULA
| Binomial transform of 1, 1, 1, -1.
G.f.: (-1+2*x-2*x^2+2*x^3)/(2*x-1)/(2*x^2-2*x+1). - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 14 2007
a(n)=2*A038504(n), n>0. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 17 2009]
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MATHEMATICA
| Join[{1}, LinearRecurrence[{4, -6, 4}, {2, 4, 6}, 60]] (* From Harvey P. Dale, Jul 07 2011 *)
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CROSSREFS
| Sequence in context: A140999 A168267 A001217 * A173941 A194406 A087443
Adjacent sequences: A131882 A131883 A131884 * A131886 A131887 A131888
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KEYWORD
| nonn
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AUTHOR
| Paul Curtz (bpcrtz(AT)free.fr), Oct 25 2007
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EXTENSIONS
| More terms from Harvey P. Dale, Jul 07 2011
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