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Search: id:A073748
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| A073748 |
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a(n)=S(n)*S(n-1), where S(n) are the generalized tribonacci numbers A001644. |
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+0
1
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| -3, 3, 3, 21, 77, 231, 819, 2769, 9301, 31571, 106763, 361045, 1221685, 4132743, 13980747, 47297217, 160004685, 541291715, 1831178355, 6194830005, 20956959933, 70896891079, 239842458947, 811381229009, 2744883043045, 9285872805715, 31413882695739, 106272403946805
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OFFSET
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0,1
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COMMENT
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a(n)=S(2n-1)+C(n-1)-C(n-2), where S(n) is A001644, C(n) is A073145
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FORMULA
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G.f.: ( - 3 + 9*x + 6*x^2 + 24*x^3 + 5*x^4 - x^5)/(1 - 2*x - 3*x^2 - 6*x^3 + x^4 + x^6)
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MATHEMATICA
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CoefficientList[Series[(-3+9*x+6*x^2+24*x^3+5*x^4-x^5)/(1-2*x-3*x^2-6*x^3+x^4+x^6), {x, 0, 30}], x]
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CROSSREFS
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Cf. A001644, A073145.
Sequence in context: A083562 A106542 A127014 this_sequence A131445 A033874 A122092
Adjacent sequences: A073745 A073746 A073747 this_sequence A073749 A073750 A073751
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KEYWORD
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easy,sign
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AUTHOR
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Maio Catalani (mario.catalani(AT)unito.it), Aug 08 2002
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