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Search: id:A099528
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| A099528 |
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Row sums of triangle A099527, so that a(n) = Sum_{k=0..n} coefficient of z^k in (2 + 3*z + z^2)^(n-[k/2]), where [k/2] is the integer floor of k/2. |
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+0
2
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| 1, 5, 17, 63, 242, 922, 3502, 13311, 50608, 192398, 731429, 2780649, 10571120, 40187929, 152781292, 580824261, 2208102985, 8394481949, 31913061839, 121322974122, 461230079570, 1753445197282, 6666022438759, 25342026784200
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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G.f.: (1+x-x^2)/(1-4*x+2*x^2-5*x^3+x^4).
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PROGRAM
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(PARI) a(n)=sum(k=0, n, polcoeff((2+3*z+z^2+z*O(z^k))^(n-k\2), k, z))
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CROSSREFS
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Cf. A099527.
Sequence in context: A007483 A128073 A051736 this_sequence A062229 A120893 A046231
Adjacent sequences: A099525 A099526 A099527 this_sequence A099529 A099530 A099531
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Oct 20 2004
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EXTENSIONS
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Corrected by T. D. Noe (noe(AT)sspectra.com), Oct 25 2006
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