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A157571
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Half the number of length n integer sequences with sum zero and sum of squares 3042.
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1
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1, 9, 270, 10990, 622725, 43526469, 2629049500, 142957923228, 7300452572415, 342254197570615, 14695487432860410, 589524950365892190, 22721530823371062501, 851515705898338365990, 31013728074479042288280
(list; graph; refs; listen; history; internal format)
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OFFSET
| 2,2
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LINKS
| R. H. Hardin, Table of n, a(n) for n=2..50
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FORMULA
| [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,0,3042)/2.
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CROSSREFS
| Sequence in context: A191960 A168600 A088672 * A202689 A028456 A180358
Adjacent sequences: A157568 A157569 A157570 * A157572 A157573 A157574
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KEYWORD
| nonn
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AUTHOR
| R. H. Hardin (rhhardin(AT)att.net) Mar 02 2009
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