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Search: id:A083068
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| 1, 7, 55, 439, 3511, 28087, 224695, 1797559, 14380471, 115043767, 920350135, 7362801079, 58902408631, 471219269047, 3769754152375, 30158033218999, 241264265751991, 1930114126015927, 15440913008127415, 123527304065019319
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OFFSET
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0,2
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FORMULA
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a(n)=(6*8^n+1)/7 G.f. (1-2x)/((1-8x)(1-x)) E.g.f. (6*exp(8x)+exp(x))/7
a(n)=8*a(n-1)-1 (with a(1)=1) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Oct 29 2009]
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EXAMPLE
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For n=2, a(2)=8*1-1=7: n=3, a(3)=8*7-1=55; n=4, a(4)=8*55-1=439 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Oct 29 2009]
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CROSSREFS
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Cf. A083067, A083066.
Sequence in context: A015564 A070997 A122372 this_sequence A097189 A049028 A096951
Adjacent sequences: A083065 A083066 A083067 this_sequence A083069 A083070 A083071
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KEYWORD
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easy,nonn
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Apr 21 2003
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