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Search: id:A081069
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| A081069 |
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Lucas(4n)+2, or Lucas(2n)^2. |
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+0
1
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| 4, 9, 49, 324, 2209, 15129, 103684, 710649, 4870849, 33385284, 228826129, 1568397609, 10749957124, 73681302249, 505019158609, 3461452808004, 23725150497409, 162614600673849, 1114577054219524, 7639424778862809
(list; graph; listen)
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OFFSET
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0,1
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REFERENCES
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Hugh C. Williams, Edouard Lucas and Primality Testing, John Wiley and Sons, 1998, p. 75
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FORMULA
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a(n) = 8a(n-1)-8a(n-2)+a(n-3)
a(n)=2+[(7/2)-(3/2)*sqrt(5)]^n+[(7/2)+(3/2)*sqrt(5)]^n, with n>=0 [From Paolo P. Lava (ppl(AT)spl.at), Dec 01 2008]
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MAPLE
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luc := proc(n) option remember: if n=0 then RETURN(2) fi: if n=1 then RETURN(1) fi: luc(n-1)+luc(n-2): end: for n from 0 to 40 do printf(`%d, `, luc(4*n)+2) od:
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CROSSREFS
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Cf. A000032 (Lucas numbers).
Sequence in context: A068809 A110481 A030088 this_sequence A053967 A028945 A082875
Adjacent sequences: A081066 A081067 A081068 this_sequence A081070 A081071 A081072
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KEYWORD
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nonn,easy
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AUTHOR
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R. K. Guy (rkg(AT)cpsc.ucalgary.ca), Mar 04, 2003
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EXTENSIONS
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More terms and Maple code from James A. Sellers (sellersj(AT)math.psu.edu), Mar 05, 2003
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