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Search: id:A157598
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| A157598 |
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Half the number of length n integer sequences with sum zero and sum of squares 8712. |
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+0
1
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| 1, 3, 198, 27930, 3388365, 475265259, 48238917727, 3831384879156, 290324159283540, 21674347016566915, 1571698374562433667, 110138942653526323056, 7411777323163714916688, 477289870722013730288040
(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,0,8712)/2.
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CROSSREFS
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Sequence in context: A101382 A000724 A157565 this_sequence A023310 A054701 A140654
Adjacent sequences: A157595 A157596 A157597 this_sequence A157599 A157600 A157601
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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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