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A107706
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Quadratic recurrence a(n)=2a(n-1)^2+a(n-2), a(0)=a(1)=1.
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0
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1, 1, 3, 19, 725, 1051269, 2210333021447, 9771144131398048324998887, 190950515273109040540985906104397627141067435498985, 72924198566131697919005645563941249133599421947333610081098812005030529313728193495031984760197059337
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OFFSET
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0,3
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LINKS
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FORMULA
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a(n) ~ 1/2 * c^(2^n), where c = 1.5761071725603835806427292143532632951057735784139134374711... . - Vaclav Kotesovec, Jan 19 2015
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MATHEMATICA
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RecurrenceTable[{a[n]==2*a[n-1]^2+a[n-2], a[0]==1, a[1]==1}, a, {n, 0, 10}] (* Vaclav Kotesovec, Jan 19 2015 *)
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PROG
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(PARI) a(n)=if(n<0, -a(-1-n), if(n<2, 1, 2*a(n-1)^2+a(n-2)))
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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