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Search: id:A155181
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| A155181 |
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a(n)=5*a(n-1)+a(n-2), n>2 ; a(0)=1, a(1)=4, a(2)=20 . |
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+0
1
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| 1, 4, 20, 104, 540, 2804, 14560, 75604, 392580, 2038504, 10585100, 54964004, 285405120, 1481989604, 7695353140, 39958755304, 207489129660, 1077404403604, 5594511147680, 29049960142004, 150844311857700, 783271519430504
(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)/(1-5*x-x^2).
a(n)=2*{[(5/2)+(1/2)*sqrt(29)]^(n-1)+[(5/2)-(1/2)*sqrt(29)]^(n-1)}+(10/29)*sqrt(29)*{[(5/2)+(1/2)*sqrt(29)]^(n-1)-[(5/2)-(1/2)*sqrt(29)]^(n-1)}+[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: A005054 A105480 A155485 this_sequence A082761 A076035 A120978
Adjacent sequences: A155178 A155179 A155180 this_sequence A155182 A155183 A155184
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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 21 2009
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