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Search: id:A075150
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| A075150 |
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a(n)=L(n)*C(n), L(n)=Lucas numbers (A000032), C(n)=reflected Lucas numbers (see comment to A061084). |
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+0
3
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| 4, -1, 9, -16, 49, -121, 324, -841, 2209, -5776, 15129, -39601, 103684, -271441, 710649, -1860496, 4870849, -12752041, 33385284, -87403801, 228826129, -599074576, 1568397609, -4106118241, 10749957124, -28143753121, 73681302249, -192900153616, 505019158609, -1322157322201
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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a(n)=2+(-1)^n*L(2n).
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FORMULA
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a(n)=-2a(n-1)+2a(n-2)+a(n-3), a(0)=4, a(1)=-1, a(2)=9. G.f.: (4 + 7*x - x^2)/(1 + 2*x - 2*x^2 - x^3).
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MATHEMATICA
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CoefficientList[Series[(4 + 7*x - x^2)/(1 + 2*x - 2*x^2 - x^3), {x, 0, 30}], x]
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CROSSREFS
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Cf. A000032, A061084.
Sequence in context: A091885 A069606 A001254 this_sequence A128626 A028941 A065045
Adjacent sequences: A075147 A075148 A075149 this_sequence A075151 A075152 A075153
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KEYWORD
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easy,sign
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AUTHOR
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Mario Catalani (mario.catalani(AT)unito.it), Sep 05 2002
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