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Search: id:A075193
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| A075193 |
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"Inverted" Lucas numbers (see Comments). |
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+0
4
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| 1, -3, 4, -7, 11, -18, 29, -47, 76, -123, 199, -322, 521, -843, 1364, -2207, 3571, -5778, 9349, -15127, 24476, -39603, 64079, -103682, 167761, -271443, 439204, -710647, 1149851, -1860498, 3010349, -4870847, 7881196, -12752043, 20633239, -33385282, 54018521, -87403803, 141422324
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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The g.f. is obtained inserting 1/x into the g.f. of Lucas sequence and dividing by x. The closed form is a(n)=(-1)^n*a^(n+1)+(-1)^n*b^(n+1), where a=golden ratio and b=1-a, so that a(n)=(-1)^n*L(n+1), L(n)=Lucas numbers.
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LINKS
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Tanya Khovanova, Recursive Sequences
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FORMULA
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a(n)=-a(n-1)+a(n-2), a(0)=1, a(1)=-3. G.f.: (1-2x)/(1+x-x^2).
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MATHEMATICA
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CoefficientList[Series[(1 - 2z)/(1 + z - z^2), {z, 0, 40}], z]
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CROSSREFS
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Cf. A000032.
Adjacent sequences: A075190 A075191 A075192 this_sequence A075194 A075195 A075196
Sequence in context: A100581 A093090 A000204 this_sequence A042433 A024319 A041209
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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 07 2002
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