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Search: id:A073728
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| A073728 |
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a(n)=Sum (S(k)), k=0,..,n, where S(n) are the tribonacci generalized numbers A001644. |
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+0
1
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| 3, 4, 7, 14, 25, 46, 85, 156, 287, 528, 971, 1786, 3285, 6042, 11113, 20440, 37595, 69148, 127183, 233926, 430257, 791366, 1455549, 2677172, 4924087, 9056808, 16658067, 30638962, 56353837, 103650866, 190643665, 350648368, 644942899
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OFFSET
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0,1
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COMMENT
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a(n)=3T(n+1)+T(n), where T(n) are the tribonacci numbers A000073
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FORMULA
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a(n)=a(n-1)+a(n-2)+a(n-3), a(0)=3, a(1)=4, a(2)=7. G.f.: (3+x)/(1-x-x^2-x^3)
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MATHEMATICA
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CoefficientList[Series[(3 + x)/(1 - x - x^2 - x^3), {x, 0, 40}], x]
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CROSSREFS
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Cf. A001644, A000073.
Sequence in context: A062203 A095063 A003242 this_sequence A132407 A070035 A024368
Adjacent sequences: A073725 A073726 A073727 this_sequence A073729 A073730 A073731
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KEYWORD
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easy,nonn
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AUTHOR
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Mario Catalani (mario.catalani(AT)unito.it), Aug 06 2002
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