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Search: id:A133642
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| A133642 |
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a(n)=4*a(n-1)+20*a(n-2) for n>=3, a(0)=1, a(1)=4, a(2)=32 . |
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+0
2
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| 1, 4, 32, 208, 1472, 10048, 69632, 479488, 3310592, 22832128, 157540352, 1086803968, 7498022912, 51728171008, 356873142272, 2462055989848, 16985686802432, 117183866994688, 808449204027392, 5577474156003328
(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.: (1-4*x^2)/(1-4*x-20*x^2) . a(n) = Sum_{k, 0<=k<=n}A122950(n,k)*4^k .
a(n)=-[2-2*sqrt(6)]^(n-1)*sqrt(6)+sqrt(6)*[2+2*sqrt(6)]^(n-1)+2*[2-2*sqrt(6)]^(n-1)+2*[2+2 *sqrt(6)]^(n-1)+1/5*[C(2*n,n) mod 2], with n>=0 [From Paolo P. Lava (ppl(AT)spl.at), Nov 18 2008]
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CROSSREFS
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Sequence in context: A099133 A043018 A002012 this_sequence A098981 A120917 A099269
Adjacent sequences: A133639 A133640 A133641 this_sequence A133643 A133644 A133645
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KEYWORD
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easy,nonn,new
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AUTHOR
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Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Dec 31 2007
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