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Search: id:A157597
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| A157597 |
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Half the number of length n integer sequences with sum zero and sum of squares 8450. |
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+0
2
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| 1, 9, 630, 48670, 4293525, 358348053, 32224041500, 2966406894648, 259556693304825, 20157653282906667, 1439903350550159550, 97064374251531230622, 6271845201623139087495, 391742584864070048279685
(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,0,8450)/2.
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CROSSREFS
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Sequence in context: A139107 A085530 A158881 this_sequence A128795 A081232 A020548
Adjacent sequences: A157594 A157595 A157596 this_sequence A157598 A157599 A157600
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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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