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Search: id:A147837
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| A147837 |
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a(n)=7*a(n-1)-5*a(n-2), a(0)=1, a(1)=5 . |
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+0
3
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| 1, 5, 30, 185, 1145, 7090, 43905, 271885, 1683670, 10426265, 64565505, 399827210, 2475962945, 15332604565, 94948417230, 587975897785, 3641089198345, 22547744899490, 139628768304705, 864662653635485, 5354494733924870
(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)=Sum_{k, 0<=k<=n}A147703(n,k)*4^k. G.f.: (1-2x)/(1-7x+5*x^2).
a(n)=(1/2)*[(7/2)-(1/2)*sqrt(29)]^n-(3/58)*[(7/2)-(1/2)*sqrt(29)]^n*sqrt(29)+(3/58)*sqrt(29)*[(7/2)+(1 /2)*sqrt(29)]^n+1/2*[(7/2)+(1/2)*sqrt(29)]^n, with n>=0 [From Paolo P. Lava (ppl(AT)spl.at), Nov 18 2008]
a(n)= ((29+7*sqrt(29))/58)*(3.5+0.5*sqrt(29)^n +((29-7*sqrt(29))/58)*(3.5-0.5*sqrt(29)^n [From Richard Choulet (richardchoulet(AT)yahoo.fr), Nov 20 2008]
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CROSSREFS
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Sequence in context: A052934 A136785 A155195 this_sequence A076036 A161407 A006773
Adjacent sequences: A147834 A147835 A147836 this_sequence A147838 A147839 A147840
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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), Nov 14 2008
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