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Search: id:A113845
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| A113845 |
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a(1) =a(2) =1. a(n+1) = (product{1<=k<=n/2} a(k)) + (product{n/2<j<=n} a(j)). |
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+0
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| 1, 1, 2, 3, 7, 43, 905, 817217, 222613996891, 49556991610450473684541, 350842202496894090472936261713260177362896247, 12309025105287163797152809607718355345751135122592246827855872312265215391047767\ 4845042677
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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a(13) has 177 digits. - Emeric Deutsch (deutsch(AT)duke.poly.edu), Feb 06 2006
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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EXAMPLE
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(1*1*2) + (3*8*50*1202) = 1442402.
a(8)=(a(1)*a(2)*a(3))+(a(4)*a(5)*a(6)*a(7))=(1*1*2)+(3*7*43*905)=817217.
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MAPLE
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a[1]:=1: a[2]:=1: for n from 2 to 12 do a[n+1]:=product(a[k], k=1..floor(n/2))+product(a[j], j=1+floor(n/2)..n) od:seq(a[n], n=1..12); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Feb 06 2006
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CROSSREFS
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Sequence in context: A072714 A051786 A133400 this_sequence A072713 A129871 A000058
Adjacent sequences: A113842 A113843 A113844 this_sequence A113846 A113847 A113848
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KEYWORD
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easy,nonn
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AUTHOR
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Leroy Quet Jan 24 2006
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EXTENSIONS
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Corrected and extended by Emeric Deutsch (deutsch(AT)duke.poly.edu), Feb 06 2006
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