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Search: id:A152107
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| A152107 |
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((6+sqrt5)^n+(6-sqrt5)^n)^n/2 |
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+0
1
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| 1, 6, 41, 306, 2401, 19326, 157481, 1290666, 10606081, 87262326, 718359401, 5915180706, 48713027041, 401185722606, 3304124833001, 27212740595226, 224125017319681, 1845905249384166, 15202987455699881, 125212786737489426
(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)=12*a(n-1)-31*a(n-2), n>1 ; a(0)=1, a(1)=6 . G.f.: (1-6*x)/(1-12*x+31*x^2). a(n)=(Sum_{k, 0<=k<=n}A098158(n,k)*6^(2*k)*5^(n-k))/6^n . [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Nov 26 2008]
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EXAMPLE
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a(3)=306
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PROGRAM
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(MAGMA) Z<x>:= PolynomialRing(Integers()); N<r5>:=NumberField(x^2-5); S:=[ ((6+r5)^n+(6-r5)^n)/2: n in [0..19] ]; [ 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: A122371 A083067 A000402 this_sequence A143023 A078009 A127848
Adjacent sequences: A152104 A152105 A152106 this_sequence A152108 A152109 A152110
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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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