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Search: id:A161938
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| A161938 |
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a(n) = ((3+sqrt(2))*(2+sqrt(2))^n+(3-sqrt(2))*(2-sqrt(2))^n)/2. |
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+0
2
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| 3, 8, 26, 88, 300, 1024, 3496, 11936, 40752, 139136, 475040, 1621888, 5537472, 18906112, 64549504, 220385792, 752444160, 2569005056, 8771131904, 29946517504, 102243806208, 349082189824, 1191841146880, 4069200207872
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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Second binomial transform of A162255.
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FORMULA
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a(n) = 4*a(n-1)-2*a(n-2) for n>1; a(0) = 3; a(1) = 8.
G.f.: (3-4*x)/(1-4*x+2*x^2).
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PROGRAM
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(MAGMA) Z<x>:=PolynomialRing(Integers()); N<r>:=NumberField(x^2-2); S:=[ ((3+r)*(2+r)^n+(3-r)*(2-r)^n)/2: n in [0..23] ]; [ Integers()!S[j]: j in [1..#S] ]; [From Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jul 01 2009]
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CROSSREFS
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Cf. A162255, A135532, A083878.
Sequence in context: A148812 A148813 A148814 this_sequence A151444 A151458 A148815
Adjacent sequences: A161935 A161936 A161937 this_sequence A161939 A161940 A161941
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KEYWORD
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nonn
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AUTHOR
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Al Hakanson (hawkuu(AT)gmail.com), Jun 22 2009, Jun 29 2009
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EXTENSIONS
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Edited and extended beyond a(5) by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jul 01 2009
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