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Search: id:A155127
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| A155127 |
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a(n)=6*a(n-1)+6*a(n-2), n>2 ; a(0)=1, a(1)=5, a(2)=35 . |
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1
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| 1, 5, 35, 240, 1650, 11340, 77940, 535680, 3681720, 25304400, 173916720, 1195326720, 8215460640, 56464724160, 388081108800, 2667274997760, 18332136639360, 125996469822720, 865971638772480, 5951808651571200
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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)/(1-6*x-6*x^2) .
a(n)=(2/3)*sqrt(15)*{[3+sqrt(15)]^(n-1)-[3-sqrt(15)]^(n-1)}+(5/2)*{[3+sqrt(15)]^(n-1)+[3-sqrt(15)]^(n-1)}+(1/6)*[C(2*n,n) mod 2], with n>=0 [From Paolo P. Lava (ppl(AT)spl.at), Jan 26 2009]
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CROSSREFS
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Sequence in context: A154780 A007995 A091928 this_sequence A104532 A087630 A084135
Adjacent sequences: A155124 A155125 A155126 this_sequence A155128 A155129 A155130
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KEYWORD
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nonn
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AUTHOR
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Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Jan 20 2009
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