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Search: id:A157591
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| A157591 |
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Half the number of length n integer sequences with sum zero and sum of squares 6962. |
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+0
1
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| 1, 3, 354, 35410, 3079815, 254391501, 20017977868, 1645049437956, 130713839323245, 9274041450918255, 602446992143570574, 36862449524697504786, 2161188475320550751257, 122528449769743353508305
(list; graph; listen)
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OFFSET
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2,2
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LINKS
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Ron Hardin, Table of n, a(n) for n=2..50
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FORMULA
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[cache enabling] count(n,s,ss)->count(n,t,tt) where t=s mod n, q=(t-s)/n, tt=ss+2*q*s+n*q^2; count(n,t,tt)=sum[i^2<=tt]{ count(n-1,t-i,tt-i^2) }. a(n)=count(n,0,6962)/2.
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CROSSREFS
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Sequence in context: A057121 A039515 A037302 this_sequence A005336 A062226 A110717
Adjacent sequences: A157588 A157589 A157590 this_sequence A157592 A157593 A157594
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KEYWORD
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nonn
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AUTHOR
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Ron Hardin (rhhardin(AT)att.net) Mar 02 2009
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