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Search: id:A074392
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| A074392 |
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Lucas(n+1) + [3(-1)^n - 1]/2. |
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+0
4
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| 2, 1, 5, 5, 12, 16, 30, 45, 77, 121, 200, 320, 522, 841, 1365, 2205, 3572, 5776, 9350, 15125, 24477, 39601, 64080, 103680, 167762, 271441, 439205, 710645, 1149852, 1860496, 3010350, 4870845, 7881197, 12752041, 20633240, 33385280, 54018522
(list; graph; listen)
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OFFSET
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0,1
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FORMULA
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a(n)= Sum (L(2i+e), (i=0, 1, .., Floor(n/2))), where L(n) are Lucas numbers and e=2(n/2 - Floor(n/2)).
Convolution of L(n) with the sequence (1, 0, 1, 0, 1, 0, ...)
a(n)=a(n-1)+2a(n-2)-a(n-3)-a(n-4), a(0)=2, a(1)=1, a(2)=5, a(3)=5. G.f.: (2-x)/(1-x-2x^2+x^3+x^4).
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MATHEMATICA
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CoefficientList[Series[(2-x)/(1-x-2*x^2+x^3+x^4), {x, 0, 40}], x]
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CROSSREFS
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Cf. A000032, A074331.
Cf. A004146.
Sequence in context: A152290 A032006 A167158 this_sequence A052547 A096976 A119245
Adjacent sequences: A074389 A074390 A074391 this_sequence A074393 A074394 A074395
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KEYWORD
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easy,nonn
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AUTHOR
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Mario Catalani (mario.catalni(AT)unito.it), Aug 22 2002
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