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Search: id:A074081
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| A074081 |
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Sum of determinants of 3rd order principal minors of powers of inverse of tetramatrix ((1,1,0,0),(1,0,1,0),(1,0,0,1),(1,0,0,0)). |
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+0
4
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| 4, -1, 3, -7, 15, -26, 51, -99, 191, -367, 708, -1365, 2631, -5071, 9775, -18842, 36319, -70007, 134943, -260111, 501380, -966441, 1862875, -3590807, 6921503, -13341626, 25716811, -49570747, 95550687, -184179871, 355018116, -684319421, 1319068095, -2542585503, 4900991135
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OFFSET
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0,1
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COMMENT
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a(n)=(-1)^nT(n), where T(n) are the generalized tetranacci numbers A073817
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FORMULA
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a(n)=-a(n-1)+a(n-2)-a(n-3)+a(n-4), a(0)=4, a(1)=-1, a(2)=3, a(3)=-7. G.f.: (4+3x-2x^2+x^3)/(1+x-x^2+x^3-x^4).
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MATHEMATICA
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CoefficientList[Series[4+3*x-2*x^2+x^3)/(1+x-x^2+x^3-x^4), {x, 0, 40}], x]
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CROSSREFS
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Cf. A000078, A001630, A073817 (another version), A073937.
Sequence in context: A151861 A109531 A073817 this_sequence A132703 A154182 A093735
Adjacent sequences: A074078 A074079 A074080 this_sequence A074082 A074083 A074084
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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), Aug 19 2002
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