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A135055
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Pentanacci numbers: a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4) + a(n-5) for n>4 and with a(0)=-2, a(1)=-1, a(2)=0, a(3)=1, a(4)=2.
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3
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-2, -1, 0, 1, 2, 0, 2, 5, 10, 19, 36, 72, 142, 279, 548, 1077, 2118, 4164, 8186, 16093, 31638, 62199, 122280, 240396, 472606, 929119, 1826600, 3591001, 7059722, 13879048, 27285490, 53641861, 105457122, 207323243, 407586764, 801294480, 1575303470, 3096965079, 6088473036, 11969622829
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OFFSET
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0,1
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LINKS
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FORMULA
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G.f.: (1-2*x)*(x+1)*(2*x^2+x+2)/(-1+x+x^2+x^3+x^4+x^5).
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MATHEMATICA
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a[n_] := a[n] = a[n - 1] + a[n - 2] + a[n - 3] + a[n - 4] + a[n - 5]; a[0] = -2; a[1] = -1; a[2] = 0; a[3] = 1; a[4] = 2; Table[a[n], {n, 0, 50}] (* Artur Jasinski, Nov 15 2007 *)
LinearRecurrence[{1, 1, 1, 1, 1}, {-2, -1, 0, 1, 2}, 50] (* G. C. Greubel, Sep 21 2016 *)
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PROG
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(Magma) I:=[-2, -1, 0, 1, 2]; [n le 5 select I[n] else Self(n-1)+Self(n-2)+Self(n-3)+Self(n-4)+Self(n-5): n in [1..40]]; // Vincenzo Librandi, Sep 22 2016
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CROSSREFS
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KEYWORD
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sign,easy
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AUTHOR
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STATUS
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approved
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