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Search: id:A152108
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| A152108 |
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((7+sqrt5)^n+(7-sqrt5)^n)/2 |
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+0
1
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| 1, 7, 54, 448, 3896, 34832, 316224, 2894528, 26609536, 245174272, 2261620224, 20875015168, 192738922496, 1779844247552, 16437306875904, 151809149370368, 1402086588645376, 12949609668739072, 119602725461950464
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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a(n)=14*a(n-1)-44*a(n-2), n>1 ; a(0)=1, a(1)=7 . G.f.: (1-7*x)/(1-14*x+44*x^2). a(n)=(Sum_{k, 0<=k<=n}A098158(n,k)*7^(2*k)*5^(n-k))/7^n . [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 26 2008]
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EXAMPLE
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a(3)=448
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PROGRAM
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(MAGMA) Z<x>:= PolynomialRing(Integers()); N<r5>:=NumberField(x^2-5); S:=[ ((7+r5)^n+(7-r5)^n)/2: n in [0..18] ]; [ Integers()!S[j]: j in [1..#S] ]; [From Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Nov 26 2008]
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CROSSREFS
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Sequence in context: A081008 A116472 A015562 this_sequence A093742 A014509 A084065
Adjacent sequences: A152105 A152106 A152107 this_sequence A152109 A152110 A152111
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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), Nov 24 2008
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EXTENSIONS
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Extended beyond a(6) by Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Nov 26 2008
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